diff --git a/app/controllers/discourse_calendar/invitees_controller.rb b/app/controllers/discourse_calendar/invitees_controller.rb
new file mode 100644
index 00000000..d6f1d2ba
--- /dev/null
+++ b/app/controllers/discourse_calendar/invitees_controller.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+module DiscourseCalendar
+  class InviteesController < ::ApplicationController
+    before_action :ensure_logged_in
+
+    def index
+      post_event_invitees = PostEvent.find(params['post-event-id']).invitees
+
+      if params[:filter]
+        post_event_invitees = post_event_invitees.joins(:user).where("users.username LIKE '%#{params[:filter]}%'")
+      end
+
+      render json: ActiveModel::ArraySerializer.new(post_event_invitees.limit(10), each_serializer: InviteeSerializer).as_json
+    end
+
+    def update
+      invitee = Invitee.find(params[:id])
+      guardian.ensure_can_act_on_invitee!(invitee)
+      status = Invitee.statuses[invitee_params[:status].to_sym]
+      invitee.update_attendance(status: status)
+      invitee.post_event.publish_update!
+      render json: InviteeSerializer.new(invitee)
+    end
+
+    def create
+      status = Invitee.statuses[invitee_params[:status].to_sym]
+      post_event = PostEvent.find(invitee_params[:post_id])
+      guardian.ensure_can_act_on_post_event!(post_event)
+      invitee = Invitee.create!(
+        status: status,
+        post_id: invitee_params[:post_id],
+        user_id: current_user.id,
+      )
+      invitee.post_event.publish_update!
+      render json: InviteeSerializer.new(invitee)
+    end
+
+    private
+
+    def invitee_params
+      params.require(:invitee).permit(:status, :post_id)
+    end
+  end
+end
diff --git a/app/controllers/discourse_calendar/post_events_controller.rb b/app/controllers/discourse_calendar/post_events_controller.rb
new file mode 100644
index 00000000..52891cd1
--- /dev/null
+++ b/app/controllers/discourse_calendar/post_events_controller.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+module DiscourseCalendar
+  class PostEventsController < ::ApplicationController
+    before_action :ensure_logged_in
+
+    def index
+      post_events = PostEvent.visible.where("starts_at > ?", Time.now).limit(10)
+      render json: ActiveModel::ArraySerializer.new(
+        post_events,
+        each_serializer: PostEventSerializer,
+        scope: guardian).as_json
+    end
+
+    def show
+      post_event = DiscourseCalendar::PostEvent.find(params[:id])
+      guardian.ensure_can_see!(post_event.post)
+      serializer = PostEventSerializer.new(post_event, scope: guardian)
+      render_json_dump(serializer)
+    end
+
+    def destroy
+      post_event = DiscourseCalendar::PostEvent.find(params[:id])
+      guardian.ensure_can_act_on_post_event!(post_event)
+      post_event.publish_update!
+      post_event.destroy
+      render json: success_json
+    end
+
+    def update
+      DistributedMutex.synchronize("discourse-calendar[post-event-invitee-update]") do
+        post_event = DiscourseCalendar::PostEvent.find(params[:id])
+        guardian.ensure_can_edit!(post_event.post)
+        guardian.ensure_can_act_on_post_event!(post_event)
+        post_event.enforce_utc!(post_event_params)
+
+        case post_event_params[:status].to_i
+        when PostEvent.statuses[:private]
+          raw_invitees = Array(post_event_params[:raw_invitees])
+          post_event.update!(post_event_params.merge(raw_invitees: raw_invitees))
+          post_event.enforce_raw_invitees!
+        when PostEvent.statuses[:public]
+          post_event.update!(post_event_params.merge(raw_invitees: []))
+        when PostEvent.statuses[:standalone]
+          post_event.update!(post_event_params.merge(raw_invitees: []))
+          post_event.invitees.destroy_all
+        end
+
+        post_event.publish_update!
+        serializer = PostEventSerializer.new(post_event, scope: guardian)
+        render_json_dump(serializer)
+      end
+    end
+
+    def create
+      post_event = DiscourseCalendar::PostEvent.new(post_event_params)
+      guardian.ensure_can_edit!(post_event.post)
+      guardian.ensure_can_create_post_event!(post_event)
+      post_event.enforce_utc!(post_event_params)
+
+      case post_event_params[:status].to_i
+      when PostEvent.statuses[:private]
+        raw_invitees = Array(post_event_params[:raw_invitees])
+        post_event.update!(raw_invitees: raw_invitees)
+        post_event.fill_invitees!
+        post_event.notify_invitees!
+      when PostEvent.statuses[:public], PostEvent.statuses[:standalone]
+        post_event.update!(post_event_params.merge(raw_invitees: []))
+      end
+
+      post_event.publish_update!
+      serializer = PostEventSerializer.new(post_event, scope: guardian)
+      render_json_dump(serializer)
+    end
+
+    private
+
+    def post_event_params
+      params
+        .require(:post_event)
+        .permit(
+          :id,
+          :name,
+          :starts_at,
+          :ends_at,
+          :status,
+          :display_invitees,
+          raw_invitees: []
+        )
+    end
+  end
+end
diff --git a/app/controllers/discourse_calendar/upcoming_events_controller.rb b/app/controllers/discourse_calendar/upcoming_events_controller.rb
new file mode 100644
index 00000000..f2f15024
--- /dev/null
+++ b/app/controllers/discourse_calendar/upcoming_events_controller.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module DiscourseCalendar
+  class UpcomingEventsController < ::ApplicationController
+    before_action :ensure_logged_in
+
+    def index
+    end
+  end
+end
diff --git a/app/models/discourse_calendar/invitee.rb b/app/models/discourse_calendar/invitee.rb
new file mode 100644
index 00000000..1f321ede
--- /dev/null
+++ b/app/models/discourse_calendar/invitee.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+module DiscourseCalendar
+  class Invitee < ActiveRecord::Base
+    self.table_name = 'discourse_calendar_invitees'
+
+    belongs_to :post_event, foreign_key: :post_id
+    belongs_to :user
+
+    scope :with_status, ->(status) {
+      where(status: Invitee.statuses[status])
+    }
+
+    def self.statuses
+      @statuses ||= Enum.new(going: 0, interested: 1, not_going: 2)
+    end
+
+    def update_attendance(params)
+      self.update!(params)
+    end
+  end
+end
diff --git a/app/models/discourse_calendar/post_event.rb b/app/models/discourse_calendar/post_event.rb
new file mode 100644
index 00000000..98173524
--- /dev/null
+++ b/app/models/discourse_calendar/post_event.rb
@@ -0,0 +1,142 @@
+# frozen_string_literal: true
+
+module DiscourseCalendar
+  class PostEvent < ActiveRecord::Base
+    self.table_name = 'discourse_calendar_post_events'
+
+    def self.attributes_protected_by_default
+      super - ['id']
+    end
+
+    has_many :invitees, foreign_key: :post_id, dependent: :delete_all
+    belongs_to :post, foreign_key: :id
+
+    scope :visible, -> { where(deleted_at: nil) }
+
+    validates :name,
+      length: { in: 5..30 },
+      unless: -> (post_event) { post_event.name.blank? }
+
+    validate :raw_invitees_length
+    def raw_invitees_length
+      if self.raw_invitees && self.raw_invitees.length > 10
+        errors.add(:base, I18n.t("discourse_calendar.post_event.errors.raw_invitees_length", count: 10))
+      end
+    end
+
+    validate :ends_before_start
+    def ends_before_start
+      if self.starts_at && self.ends_at && self.starts_at >= self.ends_at
+        errors.add(:base, I18n.t("discourse_calendar.post_event.errors.ends_at_before_starts_at"))
+      end
+    end
+
+    def create_invitees(attrs)
+      timestamp = Time.now
+      attrs.map! do |attr|
+        {
+          post_id: self.id,
+          created_at: timestamp,
+          updated_at: timestamp
+        }.merge(attr)
+      end
+
+      self.invitees.insert_all!(attrs)
+    end
+
+    def notify_invitees!
+      self.invitees.where(notified: false).each do |invitee|
+        invitee.user.notifications.create!(
+          notification_type: Notification.types[:custom],
+          topic_id: self.post.topic_id,
+          post_number: self.post.post_number,
+          data: {
+            topic_title: self.post.topic.title,
+            display_username: self.post.user.username,
+            message: 'discourse_calendar.invite_user_notification'
+          }.to_json
+        )
+        invitee.update!(notified: true)
+      end
+    end
+
+    def self.statuses
+      @statuses ||= Enum.new(standalone: 0, public: 1, private: 2)
+    end
+
+    def self.display_invitees_options
+      @display_invitees_options ||= Enum.new(everyone: 0, invitees_only: 1, none: 2)
+    end
+
+    def most_likely_going(current_user, limit = SiteSetting.displayed_invitees_limit)
+      most_likely = []
+
+      if self.can_user_update_attendance(current_user)
+        most_likely << Invitee.find_or_initialize_by(
+          user_id: current_user.id,
+          post_id: self.id
+        )
+      end
+
+      most_likely << Invitee.new(
+        user_id: self.post.user_id,
+        status: Invitee.statuses[:going],
+        post_id: self.id
+      )
+
+      most_likely + self.invitees
+        .order([:status, :user_id])
+        .where.not(user_id: current_user.id)
+        .limit(limit - most_likely.count)
+    end
+
+    def publish_update!
+      self.post.publish_message!("/post-events/#{self.post.topic_id}", id: self.id)
+    end
+
+    def destroy_extraneous_invitees!
+      self.invitees.where.not(user_id: fetch_users.select(:id)).delete_all
+    end
+
+    def fill_invitees!
+      invited_users_ids = fetch_users.pluck(:id) - self.invitees.pluck(:user_id)
+      if invited_users_ids.present?
+        self.create_invitees(invited_users_ids.map { |user_id|
+          { user_id: user_id }
+        })
+      end
+    end
+
+    def fetch_users
+      @fetched_users ||= User.where(
+        id: GroupUser.where(
+          group_id: Group.where(name: self.raw_invitees).select(:id)
+        ).select(:user_id)
+      ).or(User.where(username: self.raw_invitees))
+    end
+
+    def enforce_raw_invitees!
+      self.destroy_extraneous_invitees!
+      self.fill_invitees!
+      self.notify_invitees!
+    end
+
+    def enforce_utc!(params)
+      if params['starts_at'].present?
+        params['starts_at'] = Time.parse(params['starts_at']).utc
+      end
+      if params['ends_at'].present?
+        params['ends_at'] = Time.parse(params['ends_at']).utc
+      end
+    end
+
+    def can_user_update_attendance(user)
+      self.post.user != user &&
+      self.status == PostEvent.statuses[:public] ||
+      (
+        self.status == PostEvent.statuses[:private] &&
+        self.invitees.exists?(user_id: user.id)
+      )
+    end
+  end
+end
diff --git a/app/models/guardian.rb b/app/models/guardian.rb
new file mode 100644
index 00000000..38a368c0
--- /dev/null
+++ b/app/models/guardian.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+class ::Guardian
+  module CanActOnPostEvent
+    def can_act_on_post_event?(post_event)
+      @user.staff? || @user.admin? || @user.id == post_event.post.user_id
+    end
+  end
+  prepend CanActOnPostEvent
+
+  module CanActOnInvitee
+    def can_act_on_invitee?(invitee)
+      @user.staff? || @user.admin? || @user.id == invitee.user_id
+    end
+  end
+  prepend CanActOnInvitee
+
+  module CanCreatePostEvent
+    def can_create_post_event?(post_event)
+      @user.staff? || @user.admin?
+    end
+  end
+  prepend CanCreatePostEvent
+
+  module CanJoinPostEvent
+    def can_join_post_event?(post_event)
+      post_event.status === DiscourseCalendar::PostEvent.statuses[:public] || (
+        post_event.status === DiscourseCalendar::PostEvent.statuses[:private]
+        post_event.invitees.find_by(user_id: @user.id)
+      )
+    end
+  end
+  prepend CanJoinPostEvent
+end
diff --git a/app/serializers/discourse_calendar/invitee_serializer.rb b/app/serializers/discourse_calendar/invitee_serializer.rb
new file mode 100644
index 00000000..62a28faf
--- /dev/null
+++ b/app/serializers/discourse_calendar/invitee_serializer.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module DiscourseCalendar
+  class InviteeSerializer < ApplicationSerializer
+    attributes :id, :status, :user
+
+    def status
+      object.status ? Invitee.statuses[object.status] : nil
+    end
+
+    def include_id?
+      object.id
+    end
+
+    def user
+      BasicUserSerializer.new(object.user, embed: :objects, root: false)
+    end
+  end
+end
diff --git a/app/serializers/discourse_calendar/post_event_serializer.rb b/app/serializers/discourse_calendar/post_event_serializer.rb
new file mode 100644
index 00000000..0beccc72
--- /dev/null
+++ b/app/serializers/discourse_calendar/post_event_serializer.rb
@@ -0,0 +1,125 @@
+# frozen_string_literal: true
+
+module DiscourseCalendar
+  class PostEventSerializer < ApplicationSerializer
+    attributes :id
+    attributes :creator
+    attributes :sample_invitees
+    attributes :watching_invitee
+    attributes :starts_at
+    attributes :ends_at
+    attributes :stats
+    attributes :status
+    attributes :raw_invitees
+    attributes :display_invitees
+    attributes :post
+    attributes :should_display_invitees
+    attributes :name
+    attributes :can_act_on_post_event
+    attributes :can_update_attendance
+
+    def can_act_on_post_event
+      scope.can_act_on_post_event?(object)
+    end
+
+    def status
+      PostEvent.statuses[object.status]
+    end
+
+    # lightweight post object containing
+    # only needed info for client
+    def post
+      {
+        id: object.post.id,
+        post_number: object.post.post_number,
+        url: object.post.url,
+        topic: {
+          id: object.post.topic.id,
+          title: object.post.topic.title
+        }
+      }
+    end
+
+    def should_display_invitees
+      display_invitees?
+    end
+
+    def can_update_attendance
+      object.can_user_update_attendance(scope.current_user)
+    end
+
+    def display_invitees
+      PostEvent.display_invitees_options[object.display_invitees]
+    end
+
+    def creator
+      BasicUserSerializer.new(object.post.user, embed: :objects, root: false)
+    end
+
+    def include_stats?
+      display_invitees?
+    end
+
+    def stats
+      counts = object.invitees.group(:status).count
+
+      # event creator is always going so we add one
+      going = (counts[Invitee.statuses[:going]] || 0) + 1
+      interested = counts[Invitee.statuses[:interested]] || 0
+      not_going = counts[Invitee.statuses[:not_going]] || 0
+      unanswered = counts[nil] || 0
+
+      {
+        going: going,
+        interested: interested,
+        not_going: not_going,
+        invited: going + interested + not_going + unanswered
+      }
+    end
+
+    def watching_invitee
+      if scope.current_user === object.post.user
+        watching_invitee = Invitee.new(
+          user_id: object.post.user.id,
+          status: Invitee.statuses[:going],
+          post_id: object.id
+        )
+      else
+        watching_invitee = Invitee.find_by(
+          user_id: scope.current_user.id,
+          post_id: object.id
+        )
+      end
+
+      if watching_invitee
+        InviteeSerializer.new(watching_invitee, root: false)
+      end
+    end
+
+    def include_sample_invitees?
+      display_invitees?
+    end
+
+    def sample_invitees
+      invitees = object.most_likely_going(scope.current_user)
+      ActiveModel::ArraySerializer.new(invitees, each_serializer: InviteeSerializer)
+    end
+
+    private
+
+    def display_invitees?
+      object.status != PostEvent.statuses[:standalone] &&
+      (
+        object.display_invitees == PostEvent.display_invitees_options[:everyone] ||
+        (
+          object.display_invitees == PostEvent.display_invitees_options[:invitees_only] &&
+          object.invitees.exists?(user_id: scope.current_user.id)
+        ) ||
+        (
+          object.display_invitees == PostEvent.display_invitees_options[:none] &&
+          object.post.user == scope.current_user
+        )
+      )
+    end
+  end
+end
diff --git a/app/views/upcoming-events/index.hbs b/app/views/upcoming-events/index.hbs
new file mode 100644
index 00000000..a789c9b5
--- /dev/null
+++ b/app/views/upcoming-events/index.hbs
@@ -0,0 +1 @@
+UPCOMING
diff --git a/app/views/upcoming_events/index.hbs b/app/views/upcoming_events/index.hbs
new file mode 100644
index 00000000..a789c9b5
--- /dev/null
+++ b/app/views/upcoming_events/index.hbs
@@ -0,0 +1 @@
+UPCOMING
diff --git a/assets/javascripts/discourse/adapters/discourse-calendar-adapter.js.es6 b/assets/javascripts/discourse/adapters/discourse-calendar-adapter.js.es6
new file mode 100644
index 00000000..0a631f49
--- /dev/null
+++ b/assets/javascripts/discourse/adapters/discourse-calendar-adapter.js.es6
@@ -0,0 +1,11 @@
+import RestAdapter from "discourse/adapters/rest";
+
+export default RestAdapter.extend({
+  basePath() {
+    return "/discourse-calendar/";
+  },
+
+  pathFor() {
+    return this._super(...arguments).replace("_", "-");
+  }
+});
diff --git a/assets/javascripts/discourse/adapters/invitee.js.es6 b/assets/javascripts/discourse/adapters/invitee.js.es6
new file mode 100644
index 00000000..5333c991
--- /dev/null
+++ b/assets/javascripts/discourse/adapters/invitee.js.es6
@@ -0,0 +1,3 @@
+import DiscourseCalendarAdapter from "./discourse-calendar-adapter";
+
+export default DiscourseCalendarAdapter.extend();
diff --git a/assets/javascripts/discourse/adapters/post-event.js.es6 b/assets/javascripts/discourse/adapters/post-event.js.es6
new file mode 100644
index 00000000..5333c991
--- /dev/null
+++ b/assets/javascripts/discourse/adapters/post-event.js.es6
@@ -0,0 +1,3 @@
+import DiscourseCalendarAdapter from "./discourse-calendar-adapter";
+
+export default DiscourseCalendarAdapter.extend();
diff --git a/assets/javascripts/discourse/components/event-field.js.es6 b/assets/javascripts/discourse/components/event-field.js.es6
new file mode 100644
index 00000000..8cc86e65
--- /dev/null
+++ b/assets/javascripts/discourse/components/event-field.js.es6
@@ -0,0 +1,6 @@
+import Component from "@ember/component";
+
+export default Component.extend({
+  enabled: true,
+  class: null
+});
diff --git a/assets/javascripts/discourse/controllers/event-ui-builder.js.es6 b/assets/javascripts/discourse/controllers/event-ui-builder.js.es6
new file mode 100644
index 00000000..c0295ca1
--- /dev/null
+++ b/assets/javascripts/discourse/controllers/event-ui-builder.js.es6
@@ -0,0 +1,105 @@
+import ModalFunctionality from "discourse/mixins/modal-functionality";
+import Controller from "@ember/controller";
+import { action, computed } from "@ember/object";
+import { equal } from "@ember/object/computed";
+import { extractError } from "discourse/lib/ajax-error";
+
+export default Controller.extend(ModalFunctionality, {
+  modalTitle: computed("model.isNew", {
+    get() {
+      return this.model.isNew ? "create_event_title" : "update_event_title";
+    }
+  }),
+
+  allowsInvitees: equal("model.status", "private"),
+
+  @action
+  setRawInvitees(_, newInvitees) {
+    this.set("model.raw_invitees", newInvitees);
+  },
+
+  startsAt: computed("model.starts_at", {
+    get() {
+      return this.model.starts_at;
+    }
+  }),
+
+  endsAt: computed("model.ends_at", {
+    get() {
+      return this.model.ends_at;
+    }
+  }),
+
+  standaloneEvent: equal("model.status", "standalone"),
+  publicEvent: equal("model.status", "public"),
+  privateEvent: equal("model.status", "private"),
+
+  inviteesOptions: computed("model.status", function() {
+    const options = [];
+
+    if (!this.standaloneEvent) {
+      options.push({
+        label: I18n.t("event.display_invitees.everyone"),
+        value: "everyone"
+      });
+
+      if (this.privateEvent) {
+        options.push({
+          label: I18n.t("event.display_invitees.invitees_only"),
+          value: "invitees_only"
+        });
+      }
+
+      options.push({
+        label: I18n.t("event.display_invitees.none"),
+        value: "none"
+      });
+    }
+
+    return options;
+  }),
+
+  @action
+  onChangeDates(changes) {
+    this.model.setProperties({
+      starts_at: moment(changes.from)
+        .utc()
+        .toISOString(),
+      ends_at: changes.to
+        ? moment(changes.to)
+            .utc()
+            .toISOString()
+        : null
+    });
+  },
+
+  @action
+  destroyPostEvent() {
+    bootbox.confirm(
+      I18n.t("event.ui_builder.confirm_delete"),
+      I18n.t("no_value"),
+      I18n.t("yes_value"),
+      confirmed => {
+        if (confirmed) {
+          this.model.destroyRecord().then(() => this.send("closeModal"));
+        }
+      }
+    );
+  },
+
+  @action
+  createEvent() {
+    this.model
+      .save()
+      .then(() => this.send("closeModal"))
+      .catch(e => this.flash(extractError(e), "error"));
+  },
+
+  @action
+  updateEvent() {
+    this.model
+      .save()
+      .then(() => this.send("closeModal"))
+      .catch(e => this.flash(extractError(e), "error"));
+  }
+});
diff --git a/assets/javascripts/discourse/controllers/post-event-invitees.js.es6 b/assets/javascripts/discourse/controllers/post-event-invitees.js.es6
new file mode 100644
index 00000000..7ee57aad
--- /dev/null
+++ b/assets/javascripts/discourse/controllers/post-event-invitees.js.es6
@@ -0,0 +1,28 @@
+import ModalFunctionality from "discourse/mixins/modal-functionality";
+import Controller from "@ember/controller";
+import { debounce } from "@ember/runloop";
+import { action } from "@ember/object";
+
+export default Controller.extend(ModalFunctionality, {
+  invitees: null,
+  filter: null,
+  isLoading: false,
+
+  onShow() {
+    this._fetchInvitees();
+  },
+
+  @action
+  onFilterChanged(filter) {
+    debounce(this, this._fetchInvitees, filter, 250);
+  },
+
+  _fetchInvitees(filter) {
+    this.set("isLoading", true);
+
+    this.store
+      .findAll("invitee", { "post-event-id": this.model.id, filter })
+      .then(invitees => this.set("invitees", invitees))
+      .finally(() => this.set("isLoading", false));
+  }
+});
diff --git a/assets/javascripts/discourse/controllers/upcoming-events-index.js.es6 b/assets/javascripts/discourse/controllers/upcoming-events-index.js.es6
new file mode 100644
index 00000000..c93fcb89
--- /dev/null
+++ b/assets/javascripts/discourse/controllers/upcoming-events-index.js.es6
@@ -0,0 +1,9 @@
+import Controller from "@ember/controller";
+
+export default Controller.extend({
+  loadPostEvents(params) {
+    this.store.findAll("post-event", params).then(postEvents => {
+      this.set("postEvents", postEvents);
+    });
+  }
+});
diff --git a/assets/javascripts/discourse/lib/google-calendar.js.es6 b/assets/javascripts/discourse/lib/google-calendar.js.es6
new file mode 100644
index 00000000..8ffad550
--- /dev/null
+++ b/assets/javascripts/discourse/lib/google-calendar.js.es6
@@ -0,0 +1,26 @@
+import EmberObject from "@ember/object";
+
+export default EmberObject.extend({
+  init(params = {}) {
+    this.title = params.title;
+    this.startsAt = moment(params.startsAt);
+    this.endsAt = params.endsAt ? moment(params.endsAt) : null;
+  },
+
+  generateLink() {
+    const title = encodeURIComponent(this.title);
+    let dates = [this._formatDate(this.startsAt)];
+    if (this.endsAt) {
+      dates.push(this._formatDate(this.endsAt));
+      dates = `dates=${dates.join("/")}`;
+    } else {
+      dates = `date=${dates.join("")}`;
+    }
+
+    return `https://www.google.com/calendar/event?action=TEMPLATE&text=${title}&${dates}`;
+  },
+
+  _formatDate(date) {
+    return date.toISOString().replace(/-|:|\.\d\d\d/g, "");
+  }
+});
diff --git a/assets/javascripts/discourse/models/invitee.js.es6 b/assets/javascripts/discourse/models/invitee.js.es6
new file mode 100644
index 00000000..d087ac72
--- /dev/null
+++ b/assets/javascripts/discourse/models/invitee.js.es6
@@ -0,0 +1,9 @@
+import RestModel from "discourse/models/rest";
+
+export default RestModel.extend({
+  init() {
+    this._super(...arguments);
+
+    this.__type = "invitee";
+  }
+});
diff --git a/assets/javascripts/discourse/models/post-event.js.es6 b/assets/javascripts/discourse/models/post-event.js.es6
new file mode 100644
index 00000000..9e04f1df
--- /dev/null
+++ b/assets/javascripts/discourse/models/post-event.js.es6
@@ -0,0 +1,72 @@
+import RestModel from "discourse/models/rest";
+// import { ajax } from "discourse/lib/ajax";
+
+// const BASE_URL = "/discourse-calendar/post-events";
+
+const ATTRIBUTES = {
+  id: {},
+  name: {},
+  starts_at: {},
+  ends_at: {},
+  raw_invitees: {},
+  display_invitees: {
+    transform(value) {
+      return DISPLAY_INVITEES_OPTIONS[value];
+    }
+  },
+  status: {
+    transform(value) {
+      return STATUSES[value];
+    }
+  }
+};
+
+const DISPLAY_INVITEES_OPTIONS = {
+  everyone: 0,
+  invitees_only: 1,
+  none: 2
+};
+
+const STATUSES = {
+  standalone: 0,
+  public: 1,
+  private: 2
+};
+
+const PostEvent = RestModel.extend({
+  init() {
+    this._super(...arguments);
+
+    this.__type = "post-event";
+  },
+
+  updateProperties() {
+    const attributesKeys = Object.keys(ATTRIBUTES);
+    return this.getProperties(attributesKeys);
+  },
+
+  createProperties() {
+    const attributesKeys = Object.keys(ATTRIBUTES);
+    return this.getProperties(attributesKeys);
+  },
+
+  _transformProps(props) {
+    const attributesKeys = Object.keys(ATTRIBUTES);
+    attributesKeys.forEach(key => {
+      const attribute = ATTRIBUTES[key];
+      if (attribute.transform) {
+        props[key] = attribute.transform(props[key]);
+      }
+    });
+  },
+
+  beforeUpdate(props) {
+    this._transformProps(props);
+  },
+
+  beforeCreate(props) {
+    this._transformProps(props);
+  }
+});
+
+export default PostEvent;
diff --git a/assets/javascripts/discourse/routes/upcoming-events-index.js.es6 b/assets/javascripts/discourse/routes/upcoming-events-index.js.es6
new file mode 100644
index 00000000..60b04e9f
--- /dev/null
+++ b/assets/javascripts/discourse/routes/upcoming-events-index.js.es6
@@ -0,0 +1,15 @@
+import Route from "@ember/routing/route";
+
+export default Route.extend({
+  queryParams: {
+    invited: { refreshModel: true, replace: true }
+  },
+
+  model(params) {
+    return params;
+  },
+
+  setupController(controller, params) {
+    controller.loadPostEvents(params);
+  }
+});
diff --git a/assets/javascripts/discourse/routes/upcoming-events.js.es6 b/assets/javascripts/discourse/routes/upcoming-events.js.es6
new file mode 100644
index 00000000..f7f5da26
--- /dev/null
+++ b/assets/javascripts/discourse/routes/upcoming-events.js.es6
@@ -0,0 +1,3 @@
+import Route from "@ember/routing/route";
+
+export default Route.extend({});
diff --git a/assets/javascripts/discourse/templates/components/event-field.hbs b/assets/javascripts/discourse/templates/components/event-field.hbs
new file mode 100644
index 00000000..7be8e11a
--- /dev/null
+++ b/assets/javascripts/discourse/templates/components/event-field.hbs
@@ -0,0 +1,10 @@
+{{#if enabled}}
+  <div class="event-field {{class}}">
+    <div class="event-field-label">
+      <span class="label">{{i18n label}}</span>
+    </div>
+    <div class="event-field-control">
+      {{yield}}
+    </div>
+  </div>
+{{/if}}
diff --git a/assets/javascripts/discourse/templates/modal/event-ui-builder.hbs b/assets/javascripts/discourse/templates/modal/event-ui-builder.hbs
new file mode 100644
index 00000000..b39a1681
--- /dev/null
+++ b/assets/javascripts/discourse/templates/modal/event-ui-builder.hbs
@@ -0,0 +1,122 @@
+{{#d-modal-body
+  title=(concat "event.ui_builder." modalTitle)
+  class="event-ui-builder"
+}}
+  {{#conditional-loading-section isLoading=model.isSaving}}
+  <form>
+    {{#event-field class="name" label="event.ui_builder.name.label"}}
+      {{input
+        value=(readonly model.name)
+        placeholderKey="event.ui_builder.name.placeholder"
+        input=(action (mut model.name) value="target.value")
+      }}
+    {{/event-field}}
+
+    {{date-time-input-range
+      from=startsAt
+      to=endsAt
+      onChange=(action "onChangeDates")
+    }}
+    {{#event-field label="event.ui_builder.status.label"}}
+      <label class="radio-label">
+        {{radio-button
+          name="status"
+          value="standalone"
+          selection=model.status
+          onChange=(action (mut model.status))
+        }}
+        <span class="message">
+          <span class="title">{{i18n "event.post_event_status.standalone.title"}}</span>
+          <span class="description">{{i18n "event.post_event_status.standalone.description"}}</span>
+        </span>
+      </label>
+
+      <label class="radio-label">
+        {{radio-button
+          name="status"
+          value="public"
+          selection=model.status
+          onChange=(action (mut model.status))
+        }}
+        <span class="message">
+          <span class="title">{{i18n "event.post_event_status.public.title"}}</span>
+          <span class="description">{{i18n "event.post_event_status.public.description"}}</span>
+        </span>
+      </label>
+      <label class="radio-label">
+        {{radio-button
+          name="status"
+          value="private"
+          selection=model.status
+          onChange=(action (mut model.status))
+        }}
+        <span class="message">
+          <span class="title">{{i18n "event.post_event_status.private.title"}}</span>
+          <span class="description">{{i18n "event.post_event_status.private.description"}}</span>
+        </span>
+      </label>
+    {{/event-field}}
+
+    {{#event-field enabled=allowsInvitees label="event.ui_builder.invitees.label"}}
+      {{user-selector
+        single=false
+        onChangeCallback=(action "setRawInvitees")
+        fullWidthWrap=true
+        allowAny=false
+        includeMessageableGroups=true
+        placeholderKey="composer.users_placeholder"
+        tabindex="1"
+        usernames=model.raw_invitees
+        hasGroups=true
+        autocomplete="discourse"
+        excludeCurrentUser=true
+      }}
+    {{/event-field}}
+
+    {{#if inviteesOptions.length}}
+      {{#event-field label="event.ui_builder.display_invitees.label"}}
+        {{#each inviteesOptions as |option|}}
+          <label class="radio-label">
+            {{radio-button
+              name="display_invitees"
+              value=option.value
+              selection=model.display_invitees
+              onChange=(action (mut model.display_invitees))
+            }}
+            <span class="message">
+              {{option.label}}
+             </span>
+          </label>
+        {{/each}}
+      {{/event-field}}
+    {{/if}}
+  </form>
+  {{/conditional-loading-section}}
+{{/d-modal-body}}
+
+
+<div class="modal-footer">
+  {{#if model.isNew}}
+    {{d-button
+      type="button"
+      class="btn-primary"
+      label="event.ui_builder.create"
+      icon="calendar-day"
+      action=(action "createEvent")
+    }}
+  {{else}}
+    {{d-button
+      type="button"
+      class="btn-primary"
+      label="event.ui_builder.update"
+      icon="calendar-day"
+      action=(action "updateEvent")
+    }}
+  {{/if}}
+
+  {{d-button
+    icon="trash-alt"
+    class="btn-danger"
+    action="destroyPostEvent"
+  }}
+</div>
diff --git a/assets/javascripts/discourse/templates/modal/post-event-invitees.hbs b/assets/javascripts/discourse/templates/modal/post-event-invitees.hbs
new file mode 100644
index 00000000..c303ee69
--- /dev/null
+++ b/assets/javascripts/discourse/templates/modal/post-event-invitees.hbs
@@ -0,0 +1,28 @@
+{{#d-modal-body
+  title="event.post-event-invitees-modal.title"
+}}
+  {{input
+    value=(readonly filter)
+    input=(action "onFilterChanged" value="target.value")
+    class="filter"
+    placeholderKey="event.post-event-invitees-modal.filter_placeholder"
+  }}
+
+  {{#conditional-loading-spinner condition=isLoading}}
+  <ul class="invitees">
+    {{#each invitees as |invitee|}}
+      <li class="invitee">
+        <span class="user">
+          {{avatar invitee.user imageSize="medium"}}
+          {{format-username invitee.user.username}}
+        </span>
+        {{#if invitee.status}}
+          <span class="status {{invitee.status}}">
+            {{i18n (concat "event.invitee_status." invitee.status)}}
+          </span>
+        {{/if}}
+      </li>
+    {{/each}}
+  </ul>
+  {{/conditional-loading-spinner}}
+{{/d-modal-body}}
diff --git a/assets/javascripts/discourse/templates/upcoming-events-index.hbs b/assets/javascripts/discourse/templates/upcoming-events-index.hbs
new file mode 100644
index 00000000..a535a029
--- /dev/null
+++ b/assets/javascripts/discourse/templates/upcoming-events-index.hbs
@@ -0,0 +1,31 @@
+<table class="table upcoming-events-table">
+  <thead>
+    <tr>
+      <th>id</th>
+      <th>creator</th>
+      <th>status</th>
+      <th>starts at</th>
+    </tr>
+  </thead>
+  <tbody>
+    {{#each postEvents as |postEvent|}}
+      <tr>
+        <td>
+          <a href={{postEvent.post.url}}>
+            {{format-post-event-name postEvent}}
+          </a>
+        </td>
+        <td>
+          {{avatar postEvent.creator imageSize="tiny"}}
+          {{format-username postEvent.creator.username}}
+        </td>
+        <td>
+          {{postEvent.status}}
+        </td>
+        <td>
+          {{format-future-date postEvent.starts_at}}
+        </td>
+      </tr>
+    {{/each}}
+  </tbody>
+</table>
diff --git a/assets/javascripts/discourse/templates/upcoming-events.hbs b/assets/javascripts/discourse/templates/upcoming-events.hbs
new file mode 100644
index 00000000..c24cd689
--- /dev/null
+++ b/assets/javascripts/discourse/templates/upcoming-events.hbs
@@ -0,0 +1 @@
+{{outlet}}
diff --git a/assets/javascripts/discourse/upcoming-events-route-map.js.es6 b/assets/javascripts/discourse/upcoming-events-route-map.js.es6
new file mode 100644
index 00000000..4c4cd652
--- /dev/null
+++ b/assets/javascripts/discourse/upcoming-events-route-map.js.es6
@@ -0,0 +1,5 @@
+export default function() {
+  this.route("upcoming-events", { path: "/upcoming-events" }, function() {
+    this.route("index", { path: "/" });
+  });
+}
diff --git a/assets/javascripts/widgets/discourse-group-timezone-new-day.js.es6 b/assets/javascripts/discourse/widgets/discourse-group-timezone-new-day.js.es6
similarity index 100%
rename from assets/javascripts/widgets/discourse-group-timezone-new-day.js.es6
rename to assets/javascripts/discourse/widgets/discourse-group-timezone-new-day.js.es6
diff --git a/assets/javascripts/widgets/discourse-group-timezone.js.es6 b/assets/javascripts/discourse/widgets/discourse-group-timezone.js.es6
similarity index 100%
rename from assets/javascripts/widgets/discourse-group-timezone.js.es6
rename to assets/javascripts/discourse/widgets/discourse-group-timezone.js.es6
diff --git a/assets/javascripts/widgets/discourse-group-timezones-filter.js.es6 b/assets/javascripts/discourse/widgets/discourse-group-timezones-filter.js.es6
similarity index 100%
rename from assets/javascripts/widgets/discourse-group-timezones-filter.js.es6
rename to assets/javascripts/discourse/widgets/discourse-group-timezones-filter.js.es6
diff --git a/assets/javascripts/widgets/discourse-group-timezones-header.js.es6 b/assets/javascripts/discourse/widgets/discourse-group-timezones-header.js.es6
similarity index 100%
rename from assets/javascripts/widgets/discourse-group-timezones-header.js.es6
rename to assets/javascripts/discourse/widgets/discourse-group-timezones-header.js.es6
diff --git a/assets/javascripts/widgets/discourse-group-timezones-member.js.es6 b/assets/javascripts/discourse/widgets/discourse-group-timezones-member.js.es6
similarity index 100%
rename from assets/javascripts/widgets/discourse-group-timezones-member.js.es6
rename to assets/javascripts/discourse/widgets/discourse-group-timezones-member.js.es6
diff --git a/assets/javascripts/widgets/discourse-group-timezones-reset.js.es6 b/assets/javascripts/discourse/widgets/discourse-group-timezones-reset.js.es6
similarity index 100%
rename from assets/javascripts/widgets/discourse-group-timezones-reset.js.es6
rename to assets/javascripts/discourse/widgets/discourse-group-timezones-reset.js.es6
diff --git a/assets/javascripts/widgets/discourse-group-timezones-slider.js.es6 b/assets/javascripts/discourse/widgets/discourse-group-timezones-slider.js.es6
similarity index 100%
rename from assets/javascripts/widgets/discourse-group-timezones-slider.js.es6
rename to assets/javascripts/discourse/widgets/discourse-group-timezones-slider.js.es6
diff --git a/assets/javascripts/widgets/discourse-group-timezones-time-traveler.js.es6 b/assets/javascripts/discourse/widgets/discourse-group-timezones-time-traveler.js.es6
similarity index 100%
rename from assets/javascripts/widgets/discourse-group-timezones-time-traveler.js.es6
rename to assets/javascripts/discourse/widgets/discourse-group-timezones-time-traveler.js.es6
diff --git a/assets/javascripts/widgets/discourse-group-timezones.js.es6 b/assets/javascripts/discourse/widgets/discourse-group-timezones.js.es6
similarity index 100%
rename from assets/javascripts/widgets/discourse-group-timezones.js.es6
rename to assets/javascripts/discourse/widgets/discourse-group-timezones.js.es6
diff --git a/assets/javascripts/discourse/widgets/post-event-dates.js.es6 b/assets/javascripts/discourse/widgets/post-event-dates.js.es6
new file mode 100644
index 00000000..b741d293
--- /dev/null
+++ b/assets/javascripts/discourse/widgets/post-event-dates.js.es6
@@ -0,0 +1,11 @@
+import hbs from "discourse/widgets/hbs-compiler";
+import { createWidget } from "discourse/widgets/widget";
+
+export default createWidget("post-event-dates", {
+  tagName: "section.post-event-dates",
+
+  template: hbs`
+    {{d-icon "clock"}}
+    <span class="date">{{{attrs.localDates}}}</span>
+  `
+});
diff --git a/assets/javascripts/discourse/widgets/post-event-host.js.es6 b/assets/javascripts/discourse/widgets/post-event-host.js.es6
new file mode 100644
index 00000000..05cb3d30
--- /dev/null
+++ b/assets/javascripts/discourse/widgets/post-event-host.js.es6
@@ -0,0 +1,33 @@
+import { h } from "virtual-dom";
+import { avatarImg } from "discourse/widgets/post";
+import { createWidget } from "discourse/widgets/widget";
+import { formatUsername } from "discourse/lib/utilities";
+
+export default createWidget("post-event-creator", {
+  tagName: "span.post-event-creator",
+
+  html(attrs) {
+    const { name, username, avatar_template } = attrs.user;
+
+    return h(
+      "a",
+      {
+        attributes: {
+          class: "topic-invitee-avatar",
+          "data-user-card": username
+        }
+      },
+      [
+        avatarImg("tiny", {
+          template: avatar_template,
+          username: name || formatUsername(username)
+        }),
+        h(
+          "span",
+          { attributes: { class: "username" } },
+          name || formatUsername(username)
+        )
+      ]
+    );
+  }
+});
diff --git a/assets/javascripts/discourse/widgets/post-event-invitee.js.es6 b/assets/javascripts/discourse/widgets/post-event-invitee.js.es6
new file mode 100644
index 00000000..c224afd3
--- /dev/null
+++ b/assets/javascripts/discourse/widgets/post-event-invitee.js.es6
@@ -0,0 +1,59 @@
+import { h } from "virtual-dom";
+import { avatarImg } from "discourse/widgets/post";
+import { createWidget } from "discourse/widgets/widget";
+import { formatUsername } from "discourse/lib/utilities";
+
+export default createWidget("post-event-invitee", {
+  tagName: "li.post-event-invitee",
+
+  buildClasses(attrs) {
+    return [
+      Ember.isPresent(attrs.invitee.status)
+        ? `status-${attrs.invitee.status}`
+        : `unanswered`
+    ];
+  },
+
+  html(attrs) {
+    const { name, username, avatar_template } = attrs.invitee.user;
+
+    let statusIcon;
+    switch (attrs.invitee.status) {
+      case "going":
+        statusIcon = "fa-check";
+        break;
+      case "interested":
+        statusIcon = "fa-question";
+        break;
+      case "not_going":
+        statusIcon = "fa-times";
+        break;
+    }
+
+    const avatarContent = [
+      avatarImg("large", {
+        template: avatar_template,
+        username: name || formatUsername(username)
+      })
+    ];
+
+    if (statusIcon) {
+      avatarContent.push(
+        this.attach("avatar-flair", {
+          primary_group_name: `status-${attrs.invitee.status}`,
+          primary_group_flair_url: statusIcon
+        })
+      );
+    }
+    return h(
+      "a",
+      {
+        attributes: {
+          class: "topic-invitee-avatar",
+          "data-user-card": username
+        }
+      },
+      avatarContent
+    );
+  }
+});
diff --git a/assets/javascripts/discourse/widgets/post-event-invitees.js.es6 b/assets/javascripts/discourse/widgets/post-event-invitees.js.es6
new file mode 100644
index 00000000..96f6b162
--- /dev/null
+++ b/assets/javascripts/discourse/widgets/post-event-invitees.js.es6
@@ -0,0 +1,43 @@
+import hbs from "discourse/widgets/hbs-compiler";
+import { createWidget } from "discourse/widgets/widget";
+
+export default createWidget("post-event-invitees", {
+  tagName: "section.post-event-invitees",
+
+  transform(attrs) {
+    return {
+      showAll: attrs.postEvent.stats && attrs.postEvent.stats.invited > 10
+    };
+  },
+
+  template: hbs`
+    <div class="header">
+      <div class="post-event-invitees-status">
+        <span>{{attrs.postEvent.stats.going}} Going -</span>
+        <span>{{attrs.postEvent.stats.interested}} Interested -</span>
+        <span>{{attrs.postEvent.stats.not_going}} Not going -</span>
+        <span class="invited">on {{attrs.postEvent.stats.invited}} users invited</span>
+      </div>
+
+      {{#if transformed.showAll}}
+        {{attach
+          widget="button"
+          attrs=(hash
+            className="show-all btn-small"
+            label="event.post_ui.show_all"
+            action="showAllInvitees"
+            actionParam=attrs.postEvent.id
+          )
+        }}
+      {{/if}}
+    </div>
+    <ul class="post-event-invitees-avatars">
+      {{#each attrs.postEvent.sample_invitees as |invitee|}}
+        {{attach
+          widget="post-event-invitee"
+          attrs=(hash invitee=invitee)
+        }}
+      {{/each}}
+    </ul>
+  `
+});
diff --git a/assets/javascripts/discourse/widgets/post-event-status.js.es6 b/assets/javascripts/discourse/widgets/post-event-status.js.es6
new file mode 100644
index 00000000..8a1dfc37
--- /dev/null
+++ b/assets/javascripts/discourse/widgets/post-event-status.js.es6
@@ -0,0 +1,39 @@
+import { h } from "virtual-dom";
+import { createWidget } from "discourse/widgets/widget";
+
+export default createWidget("post-event-status", {
+  tagName: "select.post-event-status",
+
+  change(event) {
+    this.sendWidgetAction("changeWatchingInviteeStatus", event.target.value);
+  },
+
+  buildClasses(attrs) {
+    if (attrs.watchingInvitee) {
+      return `status-${attrs.watchingInvitee.status}`;
+    }
+  },
+
+  html(attrs) {
+    const statuses = [
+      { value: null, name: I18n.t("event.invitee_status.unknown") },
+      { value: "going", name: I18n.t("event.invitee_status.going") },
+      { value: "interested", name: I18n.t("event.invitee_status.interested") },
+      { value: "not_going", name: I18n.t("event.invitee_status.not_going") }
+    ];
+
+    const value = attrs.watchingInvitee ? attrs.watchingInvitee.status : null;
+
+    return statuses.map(status =>
+      h(
+        "option",
+        {
+          value: status.value,
+          class: `status-${status.value}`,
+          selected: status.value === value
+        },
+        status.name
+      )
+    );
+  }
+});
diff --git a/assets/javascripts/discourse/widgets/post-event.js.es6 b/assets/javascripts/discourse/widgets/post-event.js.es6
new file mode 100644
index 00000000..26811752
--- /dev/null
+++ b/assets/javascripts/discourse/widgets/post-event.js.es6
@@ -0,0 +1,184 @@
+import EmberObject from "@ember/object";
+import showModal from "discourse/lib/show-modal";
+import hbs from "discourse/widgets/hbs-compiler";
+import { createWidget } from "discourse/widgets/widget";
+import GoogleCalendar from "discourse/plugins/discourse-calendar/discourse/lib/google-calendar";
+import { routeAction } from "discourse/helpers/route-action";
+import { iconNode } from "discourse-common/lib/icon-library";
+
+export default createWidget("post-event", {
+  tagName: "div.post-event",
+
+  buildKey: attrs => `post-event-${attrs.id}`,
+
+  buildAttributes(attrs) {
+    return { style: `height:${attrs.widgetHeight}px` };
+  },
+
+  buildClasses() {
+    if (this.state.postEvent) {
+      return ["has-post-event"];
+    }
+  },
+
+  showAllInvitees(postId) {
+    this.store.find("post-event", postId).then(postEvent => {
+      showModal("post-event-invitees", {
+        model: postEvent
+      });
+    });
+  },
+
+  editPostEvent(postId) {
+    this.store.find("post-event", postId).then(postEvent => {
+      showModal("event-ui-builder", {
+        model: postEvent,
+        modalClass: "event-ui-builder-modal"
+      });
+    });
+  },
+
+  changeWatchingInviteeStatus(status) {
+    if (this.state.postEvent.watching_invitee) {
+      this.store.update("invitee", this.state.postEvent.watching_invitee.id, {
+        status
+      });
+    } else {
+      this.store
+        .createRecord("invitee")
+        .save({ post_id: this.state.postEvent.id, status });
+    }
+  },
+
+  defaultState(attrs) {
+    return {
+      postEvent: attrs.postEvent
+    };
+  },
+
+  sendPMToCreator() {
+    const router = this.register.lookup("service:router")._router;
+    routeAction(
+      "composePrivateMessage",
+      router,
+      EmberObject.create(this.state.postEvent.creator),
+      EmberObject.create(this.state.postEvent.post)
+    ).call();
+  },
+
+  addToGoogleCalendar() {
+    const link = GoogleCalendar.create({
+      title: this.state.postEvent.name || this.state.postEvent.post.topic.title,
+      startsAt: this.state.postEvent.starts_at,
+      endsAt: this.state.postEvent.ends_at
+    }).generateLink();
+
+    window.open(link, "_blank");
+  },
+
+  transform() {
+    const postEvent = this.state.postEvent;
+
+    let statusIcon = "times";
+    if (postEvent.status === "private") {
+      statusIcon = "lock";
+    }
+    if (postEvent.status === "public") {
+      statusIcon = "unlock";
+    }
+
+    return {
+      postEventStatusLabel: I18n.t(
+        `event.post_event_status.${postEvent.status}.title`
+      ),
+      postEventStatusDescription: I18n.t(
+        `event.post_event_status.${postEvent.status}.description`
+      ),
+      startsAtMonth: moment(postEvent.starts_at).format("MMM"),
+      startsAtDay: moment(postEvent.starts_at).format("D"),
+      postEventName: postEvent.name || postEvent.post.topic.title,
+      statusClass: `status ${postEvent.status}`,
+      statusIcon: iconNode(statusIcon)
+    };
+  },
+
+  template: hbs`
+    {{#if state.postEvent}}
+      <header class="post-event-header">
+        <div class="post-event-date">
+          <div class="month">{{transformed.startsAtMonth}}</div>
+          <div class="day">{{transformed.startsAtDay}}</div>
+        </div>
+        <div class="post-event-info">
+          <div class="status-and-name">
+            <span class={{transformed.statusClass}} title={{transformed.postEventStatusDescription}}>
+              {{transformed.statusIcon}}
+              <span>{{transformed.postEventStatusLabel}}</span>
+            </span>
+            <span class="name">
+              {{transformed.postEventName}}
+            </span>
+          </div>
+          <span class="creators">
+            Created by {{attach widget="post-event-creator" attrs=(hash user=state.postEvent.creator)}}
+          </span>
+        </div>
+
+        {{#if state.postEvent.can_act_on_post_event}}
+          <div class="actions">
+            {{attach
+              widget="button"
+              attrs=(hash
+                className="btn-small"
+                icon="pencil-alt"
+                action="editPostEvent"
+                actionParam=state.postEvent.id
+              )
+            }}
+          </div>
+        {{/if}}
+      </header>
+
+      {{#if state.postEvent.can_update_attendance}}
+        <section class="post-event-actions">
+        {{attach
+          widget="post-event-status"
+          attrs=(hash
+            watchingInvitee=this.state.postEvent.watching_invitee
+          )
+        }}
+        </section>
+      {{/if}}
+
+      <hr />
+
+      {{attach widget="post-event-dates" attrs=(hash localDates=attrs.localDates postEvent=state.postEvent)}}
+
+      {{#if state.postEvent.should_display_invitees}}
+        <hr />
+        {{attach widget="post-event-invitees" attrs=(hash postEvent=state.postEvent)}}
+      {{/if}}
+
+      <footer class="post-event-footer">
+        {{attach
+          widget="button"
+          attrs=(hash
+            className="btn-small"
+            icon="calendar-day"
+            label="event.post_ui.add_to_calendar"
+            action="addToGoogleCalendar"
+          )
+        }}
+        {{attach
+          widget="button"
+          attrs=(hash
+            className="btn-small"
+            icon="envelope"
+            label="event.post_ui.send_pm_to_creator"
+            action="sendPMToCreator"
+          )
+        }}
+      </footer>
+    {{/if}}
+  `
+});
diff --git a/assets/javascripts/helpers/format-future-date.js.es6 b/assets/javascripts/helpers/format-future-date.js.es6
new file mode 100644
index 00000000..ca73642f
--- /dev/null
+++ b/assets/javascripts/helpers/format-future-date.js.es6
@@ -0,0 +1,5 @@
+import { htmlHelper } from "discourse-common/lib/helpers";
+
+export default htmlHelper(postEvent => {
+  return moment(postEvent.starts_at).format("LLL");
+});
diff --git a/assets/javascripts/helpers/format-post-event-name.js.es6 b/assets/javascripts/helpers/format-post-event-name.js.es6
new file mode 100644
index 00000000..332a4d5f
--- /dev/null
+++ b/assets/javascripts/helpers/format-post-event-name.js.es6
@@ -0,0 +1,5 @@
+import { htmlHelper } from "discourse-common/lib/helpers";
+
+export default htmlHelper(postEvent => {
+  return postEvent.name || postEvent.post.topic.title;
+});
diff --git a/assets/javascripts/initializers/add-event-ui-builder.js.es6 b/assets/javascripts/initializers/add-event-ui-builder.js.es6
new file mode 100644
index 00000000..c6f785a8
--- /dev/null
+++ b/assets/javascripts/initializers/add-event-ui-builder.js.es6
@@ -0,0 +1,56 @@
+import { withPluginApi } from "discourse/lib/plugin-api";
+import showModal from "discourse/lib/show-modal";
+import { Promise } from "rsvp";
+
+function initializeEventUIBuilder(api) {
+  api.decorateWidget("hamburger-menu:generalLinks", () => {
+    return {
+      icon: "calendar-day",
+      route: "upcoming-events",
+      label: "upcoming_events.title"
+    };
+  });
+
+  api.attachWidgetAction("post", "showEventUIBuilder", function(postId) {
+    return new Promise(resolve => {
+      if (postId) {
+        this.store
+          .find("post-event", postId)
+          .then(resolve)
+          .catch(() => {
+            const postEvent = this.store.createRecord("post-event");
+            postEvent.setProperties({
+              id: postId,
+              status: "public",
+              display_invitees: "everyone"
+            });
+            resolve(postEvent);
+          });
+      } else if (this.model) {
+        resolve(this.model);
+      }
+    }).then(model => {
+      showModal("event-ui-builder", {
+        model,
+        modalClass: "event-ui-builder-modal"
+      });
+    });
+  });
+
+  api.decorateWidget("post-admin-menu:after", dec => {
+    return dec.attach("post-admin-menu-button", {
+      icon: "calendar-day",
+      label: "event.ui_builder.attach",
+      action: "showEventUIBuilder",
+      actionParam: dec.attrs.id
+    });
+  });
+}
+
+export default {
+  name: "add-event-ui-builder",
+
+  initialize() {
+    withPluginApi("0.8.7", initializeEventUIBuilder);
+  }
+};
diff --git a/assets/javascripts/initializers/post-event-decorator.js.es6 b/assets/javascripts/initializers/post-event-decorator.js.es6
new file mode 100644
index 00000000..c92590e9
--- /dev/null
+++ b/assets/javascripts/initializers/post-event-decorator.js.es6
@@ -0,0 +1,139 @@
+import { cookAsync } from "discourse/lib/text";
+import WidgetGlue from "discourse/widgets/glue";
+import { getRegister } from "discourse-common/lib/get-owner";
+import { withPluginApi } from "discourse/lib/plugin-api";
+import { schedule } from "@ember/runloop";
+
+function _decoratePostEvent(api, cooked, post) {
+  _attachWidget(api, cooked, post);
+}
+
+let _glued = [];
+
+function cleanUp() {
+  _glued.forEach(g => g.cleanUp());
+  _glued = [];
+}
+
+function _attachWidget(api, cooked, postEvent) {
+  const existing = cooked.querySelector(".post-event");
+
+  if (postEvent) {
+    let widgetHeight = 170;
+    if (postEvent.should_display_invitees) {
+      widgetHeight += 125;
+    }
+
+    if (postEvent.can_update_attendance) {
+      widgetHeight += 65;
+    }
+
+    const postEventContainer = existing || document.createElement("div");
+    postEventContainer.classList.add("post-event");
+    postEventContainer.classList.add("is-loading");
+    postEventContainer.style.height = `${widgetHeight}px`;
+    postEventContainer.innerHTML = '<div class="spinner medium"></div>';
+    cooked.prepend(postEventContainer);
+
+    const dates = [];
+    let format;
+
+    const startsAt = moment(postEvent.starts_at);
+    if (
+      startsAt.hours() > 0 ||
+      startsAt.minutes() > 0 ||
+      (postEvent.ends_at &&
+        (moment(postEvent.ends_at).hours() > 0 ||
+          moment(postEvent.ends_at).minutes() > 0))
+    ) {
+      format = "LLL";
+    } else {
+      format = "LL";
+    }
+
+    dates.push(
+      `[date=${moment
+        .utc(postEvent.starts_at)
+        .format("YYYY-MM-DD")} time=${moment
+        .utc(postEvent.starts_at)
+        .format("HH:mm")} format=${format}]`
+    );
+
+    if (postEvent.ends_at) {
+      const endsAt = moment.utc(postEvent.ends_at);
+      dates.push(
+        `[date=${endsAt.format("YYYY-MM-DD")} time=${endsAt.format(
+          "HH:mm"
+        )} format=${format}]`
+      );
+    }
+
+    cookAsync(dates.join(" → ")).then(result => {
+      const glue = new WidgetGlue("post-event", getRegister(api), {
+        postEvent,
+        widgetHeight,
+        localDates: $(result.string).html()
+      });
+
+      glue.appendTo(postEventContainer);
+      _glued.push(glue);
+
+      schedule("afterRender", () => {
+        $(
+          ".discourse-local-date",
+          $(`[data-post-id="${postEvent.id}"]`)
+        ).applyLocalDates();
+      });
+    });
+  } else {
+    existing && existing.remove();
+  }
+}
+
+function initializePostEventDecorator(api) {
+  api.cleanupStream(cleanUp);
+
+  api.decorateCooked(($cooked, helper) => {
+    if (helper) {
+      const post = helper.getModel();
+      if (post.post_event) {
+        _decoratePostEvent(api, $cooked[0], post.post_event);
+      }
+    }
+  });
+
+  api.replaceIcon(
+    "notification.discourse_calendar.invite_user_notification",
+    "calendar-day"
+  );
+
+  api.modifyClass("controller:topic", {
+    subscribe() {
+      this._super(...arguments);
+      this.messageBus.subscribe("/post-events/" + this.get("model.id"), msg => {
+        const postNode = document.querySelector(
+          `.onscreen-post[data-post-id="${msg.id}"] .cooked`
+        );
+
+        if (postNode) {
+          this.store
+            .find("post-event", msg.id)
+            .then(postEvent => _decoratePostEvent(api, postNode, postEvent))
+            .catch(() => _decoratePostEvent(api, postNode));
+        }
+      });
+    },
+    unsubscribe() {
+      this.messageBus.unsubscribe("/post-events/*");
+      this._super(...arguments);
+    }
+  });
+}
+
+export default {
+  name: "post-event-decorator",
+
+  initialize() {
+    withPluginApi("0.8.7", initializePostEventDecorator);
+  }
+};
diff --git a/assets/stylesheets/common/post-event.scss b/assets/stylesheets/common/post-event.scss
new file mode 100644
index 00000000..989a7e1e
--- /dev/null
+++ b/assets/stylesheets/common/post-event.scss
@@ -0,0 +1,354 @@
+.event-ui-builder-modal {
+  .modal-inner-container {
+    min-width: 50vw;
+  }
+
+  .modal-body {
+    min-height: 200px;
+
+    .d-date-time-input-range {
+      width: auto;
+      padding: 0;
+      border: 0;
+    }
+  }
+
+  .modal-footer {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+  }
+
+  .event-field {
+    display: flex;
+    margin: 1em 0;
+    flex-direction: column;
+
+    &.name {
+      input {
+        width: 100%;
+      }
+    }
+
+    .event-field-label {
+      display: flex;
+      min-height: 1px;
+      padding-top: 0;
+      top: 0;
+      vertical-align: middle;
+      align-items: center;
+
+      .label {
+        font-weight: 700;
+        margin-bottom: 0.5em;
+      }
+    }
+
+    .event-field-control {
+      display: flex;
+      flex: 1;
+      flex-direction: column;
+
+      .radio-label {
+        display: flex;
+        align-items: center;
+        margin-bottom: 1em;
+
+        &:last-child {
+          margin-bottom: 0;
+        }
+
+        input[type="radio"] {
+          width: auto;
+          margin-right: 0.5em;
+        }
+
+        .message {
+          margin: 0 0 0 1em;
+          padding: 0;
+          display: flex;
+          flex-direction: column;
+
+          .description {
+            color: $primary-medium;
+          }
+        }
+      }
+
+      .ac-wrap {
+        max-width: 450px;
+      }
+
+      input {
+        margin: 0;
+      }
+    }
+  }
+}
+
+.post-event {
+  border: 1px solid $primary-low;
+  display: flex;
+
+  &.is-loading {
+    align-items: center;
+    justify-content: center;
+  }
+
+  &.has-post-event {
+    display: flex;
+    flex-direction: column;
+  }
+
+  .post-event-footer {
+    padding: 0.5em;
+    background: $primary-very-low;
+    margin-top: auto;
+  }
+
+  .post-event-header {
+    display: flex;
+    align-items: center;
+    padding: 1em;
+
+    .actions {
+      margin-bottom: auto;
+      margin-left: auto;
+    }
+  }
+
+  .post-event-date {
+    display: flex;
+    flex-direction: column;
+    width: auto;
+    margin-right: 1em;
+
+    .month {
+      text-align: center;
+      color: red;
+      font-size: $font-down-1;
+      text-transform: uppercase;
+    }
+
+    .day {
+      text-align: center;
+      font-weight: 500;
+      font-size: $font-up-2;
+    }
+  }
+
+  .post-event-info {
+    display: flex;
+    flex-direction: column;
+
+    .status-and-name {
+      display: inline-flex;
+      align-items: center;
+      margin-bottom: 0.25em;
+
+      .name {
+        font-weight: 700;
+        margin-left: 0.25em;
+        @include ellipsis;
+        max-width: 45vw;
+      }
+
+      .status {
+        text-transform: lowercase;
+        padding: 0.25em 0.5em;
+        font-size: $font-down-1;
+        border-radius: 3px;
+        background-color: $primary-very-low;
+        color: $primary-medium;
+        flex-wrap: no-wrap;
+        display: flex;
+        align-items: center;
+
+        .d-icon {
+          margin-right: 0.5em;
+        }
+      }
+    }
+
+    .creators {
+      color: $primary-medium;
+      font-size: $font-down-1;
+    }
+  }
+
+  .post-event-actions {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    padding: 1em;
+
+    .post-event-status {
+      &.status-going {
+        color: $success;
+      }
+
+      &.status-not_going {
+        color: $danger;
+      }
+    }
+  }
+
+  .post-event-creator {
+    .username {
+      margin-left: 0.25em;
+    }
+  }
+
+  .post-event-invitees {
+    padding: 1em;
+    overflow-y: auto;
+
+    .header {
+      display: flex;
+      justify-content: space-between;
+      align-items: center;
+      margin-bottom: 1em;
+
+      .show-all {
+        margin-left: 0.5em;
+        text-transform: lowercase;
+      }
+
+      .post-event-invitees-status {
+        font-weight: 700;
+
+        .invited {
+          font-weight: 500;
+          color: $primary-medium;
+        }
+      }
+    }
+
+    .post-event-invitees-avatars {
+      padding: 0;
+      margin: 0;
+      display: inline-flex;
+      flex-wrap: wrap;
+
+      .post-event-invitee {
+        list-style: none;
+        margin-right: 0.5em;
+        margin-bottom: 0.5em;
+
+        &.unanswered {
+          opacity: 0.25;
+        }
+      }
+
+      .topic-invitee-avatar {
+        position: relative;
+        display: flex;
+
+        .avatar-flair {
+          position: absolute;
+          right: 0;
+          bottom: 0;
+          background: $secondary;
+          border-radius: 50%;
+          height: 16px;
+          width: 16px;
+          display: flex;
+          align-items: center;
+          justify-content: center;
+          color: $primary-medium;
+          border: 1px solid $primary-low;
+
+          &.avatar-flair-status-going {
+            color: $success;
+          }
+
+          &.avatar-flair-status-not_going {
+            color: $danger;
+          }
+
+          .d-icon {
+            font-size: $font-down-3;
+          }
+        }
+      }
+    }
+  }
+
+  hr {
+    margin: 0;
+  }
+
+  .post-event-dates {
+    display: flex;
+    align-items: center;
+    padding: 1em;
+
+    .d-icon {
+      color: $primary-medium;
+    }
+
+    .date {
+      color: $primary-high;
+      margin-left: 1em;
+
+      .discourse-local-date {
+        .d-icon {
+          display: none;
+        }
+      }
+    }
+
+    .separator {
+      color: $primary-high;
+      margin: 0 0.5em;
+      text-align: center;
+    }
+  }
+}
+
+.post-event-invitees-modal {
+  .filter {
+    width: 100%;
+  }
+  .invitees {
+    display: flex;
+    padding: 0;
+    margin: 0;
+    flex-direction: column;
+    .invitee {
+      list-style: none;
+      display: flex;
+      flex: 1;
+      padding: 0.5em;
+      justify-content: space-between;
+      align-items: center;
+      border-bottom: 1px solid $primary-low;
+
+      &:last-child {
+        border: none;
+      }
+
+      .status {
+        margin-left: 1em;
+
+        &.going {
+          color: $success;
+        }
+
+        &.not_going {
+          color: $danger;
+        }
+      }
+    }
+  }
+}
+
+.upcoming-events-table {
+  width: 100%;
+
+  tbody {
+    tr td {
+      padding: 0.5em;
+    }
+  }
+}
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index ea8a3079..e6267848 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -1,6 +1,7 @@
 en:
   js:
     discourse_calendar:
+      invite_user_notification: "%{username} invited you to: %{description}"
       on_holiday: "On Holiday"
       holiday: "Holiday"
       add_to_calendar: "Add to calendar"
@@ -8,6 +9,51 @@ en:
         title: "Timezone"
         instructions: "Your current timezone is %{timezone}."
         none: "Select a timezone..."
+    event:
+      display_invitees:
+        everyone: "To everyone"
+        invitees_only: "To invited users only"
+        none: "Do not display invited users"
+      invitee_status:
+        unknown: "Undecided?"
+        going: "✓ Going"
+        not_going: "× Not Going"
+        interested: "? Interested"
+      post_event_status:
+        standalone:
+          title: Standalone
+          description: "A standalone event can't be joined."
+        public:
+          title: Public
+          description: "A public event can be joined by anyone."
+        private:
+          title: Private
+          description: "A private event can only be joined by invited users."
+      post_ui:
+        show_all: show all
+        add_to_calendar: add to calendar
+        send_pm_to_creator: contact
+      post-event-invitees-modal:
+        title: "List of invited users"
+        filter_placeholder: "Filter invited users"
+      ui_builder:
+        create_event_title: Create Event
+        update_event_title: Update Event
+        confirm_delete: Are you sure you want to delete this event?
+        create: Create
+        update: Save
+        attach: Create event
+        name:
+          label: Event name
+          placeholder: Optional, defaults to topic title
+        invitees:
+          label: Invited users/groups
+        status:
+          label: Status
+        display_invitees:
+          label: Display invited users
+    upcoming_events:
+      title: Upcoming events
     group_timezones:
       search: "Search..."
       group_availability: "%{group} availability"
diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index 59c3d3a4..61f75adf 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -1,6 +1,7 @@
 en:
   site_settings:
     calendar_enabled: "Enable the discourse-calendar plugin. This will add support for a [calendar][/calendar] tag in the first post of a topic."
+    events_enabled: "Enables users to create events on a topic."
     holiday_calendar_topic_id: "Topic ID of staffs holiday / absence calendar."
     delete_expired_event_posts_after: "Posts with expired events will be automatically deleted after (n) hours. Set to -1 to disable deletion."
     all_day_event_start_time: "Events that do not have a start time specified will start at this time. Format is HH:mm. For 6:00 am, enter 06:00"
@@ -13,7 +14,12 @@ en:
     working_day_end_hour: "End time of the working day hours."
     close_to_working_day_hours_extension: "Set extension time in working day hours to highlight the timezones."
   discourse_calendar:
+    invite_user_notification: "%{username} invited you to: %{description}"
     calendar_must_be_in_first_post: "Calendar tag can only be used in first post of a topic."
     more_than_one_calendar: "You can’t have more than one calendar in a post."
     more_than_two_dates: "A post of a calendar topic can’t contain more than two dates."
     event_expired: "Event expired"
+    post_event:
+      errors:
+        raw_invitees_length: "An event is limited to %{count} users/groups"
+        ends_at_before_starts_at: "An event can't end before it starts"
diff --git a/config/settings.yml b/config/settings.yml
index ae2ac0e0..dfa1b6ef 100644
--- a/config/settings.yml
+++ b/config/settings.yml
@@ -2,6 +2,9 @@ plugins:
   calendar_enabled:
     default: false
     client: true
+  events_enabled:
+    default: true
+    client: true
   holiday_calendar_topic_id:
     default: ""
     client: true
@@ -40,3 +43,7 @@ plugins:
   close_to_working_day_hours_extension:
     default: 2
     client: true
+  displayed_invitees_limit:
+    default: 10
+    client: false
+    max: 25
diff --git a/db/migrate/20201303000001_create_post_events_table.rb b/db/migrate/20201303000001_create_post_events_table.rb
new file mode 100644
index 00000000..1f3c758c
--- /dev/null
+++ b/db/migrate/20201303000001_create_post_events_table.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+class CreatePostEventsTable < ActiveRecord::Migration[5.2]
+  def up
+    create_table :discourse_calendar_post_events, id: false do |t|
+      t.bigint :id, null: false, primary_key: true
+      t.integer :status, default: 0, null: false
+      t.integer :display_invitees, default: 0, null: false
+      t.datetime :starts_at, null: false, default: -> { 'CURRENT_TIMESTAMP' }
+      t.datetime :ends_at
+      t.datetime :deleted_at
+      t.string :raw_invitees, array: true
+      t.string :name
+    end
+  end
+
+  def down
+    drop_table :discourse_calendar_post_events
+  end
+end
diff --git a/db/migrate/20201303000002_create_invitees_table.rb b/db/migrate/20201303000002_create_invitees_table.rb
new file mode 100644
index 00000000..cb3432be
--- /dev/null
+++ b/db/migrate/20201303000002_create_invitees_table.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+class CreateInviteesTable < ActiveRecord::Migration[5.2]
+  def up
+    create_table :discourse_calendar_invitees do |t|
+      t.integer :post_id, null: false
+      t.integer :user_id, null: false
+      t.integer :status
+      t.timestamps null: false
+      t.boolean :notified, null: false, default: false
+    end
+
+    add_index :discourse_calendar_invitees, [:post_id, :user_id], unique: true
+  end
+
+  def down
+    drop_table :discourse_calendar_invitees
+  end
+end
diff --git a/lib/time_sniffer.rb b/lib/time_sniffer.rb
new file mode 100644
index 00000000..75e98da9
--- /dev/null
+++ b/lib/time_sniffer.rb
@@ -0,0 +1,357 @@
+# frozen_string_literal: true
+
+class TimeSniffer
+  Interval = Struct.new(:from, :to)
+  Event = Struct.new(:at)
+
+  Context = Struct.new(:at, :timezone, :date_order)
+
+  class SniffedTime
+    attr_reader :year
+    attr_reader :month
+    attr_reader :day
+    attr_reader :hours
+    attr_reader :minutes
+    attr_reader :seconds
+    attr_reader :zone
+
+    def initialize(year:, month:, day:, hours: 0, minutes: 0, seconds: 0, zone:)
+      @year = year
+      @month = month
+      @day = day
+      @hours = hours
+      @minutes = minutes
+      @seconds = seconds
+      @zone = zone
+    end
+
+    def self.from_datetime(obj, zone)
+      new(
+        year: obj.year,
+        month: obj.month,
+        day: obj.day,
+        hours: obj.hour,
+        minutes: obj.minute,
+        seconds: obj.second,
+        zone: zone
+      )
+    end
+
+    def to_time
+      Time.use_zone(self.zone) do
+        Time.zone.parse("#{self.year}-#{self.month}-#{self.day} #{self.hours}:#{self.minutes}:#{self.seconds}")
+      end
+    end
+
+    def with(**args)
+      SniffedTime.new(**to_hash.merge(args))
+    end
+
+    def to_hash
+      {
+        year: self.year,
+        month: self.month,
+        day: self.day,
+        hours: self.hours,
+        minutes: self.minutes,
+        seconds: self.seconds,
+        zone: self.zone,
+      }
+    end
+
+    def ==(other)
+      return false unless other.kind_of?(SniffedTime)
+      return false if @year != other.year
+      return false if @month != other.month
+      return false if @day != other.day
+      return false if @hours != other.hours
+      return false if @minutes != other.minutes
+      return false if @seconds != other.seconds
+      return false if @zone != other.zone
+      true
+    end
+  end
+
+  class << self
+    def matchers
+      @matchers ||= {}
+    end
+
+    def matcher(name, regex, &blk)
+      matchers[name] = {
+        regex: regex,
+        blk: blk,
+      }
+    end
+  end
+
+  class Parser
+    UTC_REGEX = / ?(Z|UTC)/
+
+    def initialize(input, context)
+      @input = input
+      @context = context
+      @offset = 0
+    end
+
+    def parse_timezone
+      m = input_from_offset.match(UTC_REGEX)
+      if m && m.offset(0)[0] == 0
+        self.offset += m.offset(0)[1]
+        "UTC"
+      end
+    end
+
+    def parse_space
+      if input[offset] == ' '
+        self.offset += 1
+        true
+      else
+        false
+      end
+    end
+
+    def parse_time(relative_to, immediate:)
+      time, start_offset, stop_offset = peek_time(relative_to)
+      if time && (!immediate || start_offset == 0)
+        self.offset += stop_offset
+        time
+      end
+    end
+
+    def parse_date
+      date_match = DATE_REGEX.match(input_from_offset)
+      if date_match
+        day, month =
+          case @context.date_order
+          when :us
+            [date_match[2], date_match[1]]
+          when :sane
+            [date_match[1], date_match[2]]
+          end
+
+        year = date_match[3]
+        year =
+          case year.size
+          when 2
+            century = @context.at.year - (@context.at.year % 100)
+            last_century = century - 100
+
+            choices = [
+              century + year.to_i,
+              last_century + year.to_i,
+            ]
+
+            choices.sort_by { |x|
+              (@context.at.year - x).abs
+            }[0]
+          when 4
+            year.to_i
+          end
+
+        result =
+          SniffedTime.new(
+            year: year,
+            month: month.to_i,
+            day: day.to_i,
+            zone: @context.timezone,
+          )
+
+        self.offset += date_match.offset(0)[1]
+        result
+      end
+    end
+
+    def parse_time_with_timezone(relative_to, immediate:)
+      result = parse_time(relative_to, immediate: immediate)
+      if result
+        zone = parse_timezone
+
+        if zone
+          result = result.with(zone: zone)
+        end
+
+        result
+      end
+    end
+
+    def parse_date_time(relative_to)
+      date = parse_date
+      if date
+        if parse_space
+          datetime = parse_time_with_timezone(date, immediate: true)
+          if datetime
+            [false, datetime]
+          else
+            [true, date]
+          end
+        else
+          [true, date]
+        end
+      elsif relative_to
+        datetime = parse_time_with_timezone(relative_to, immediate: false)
+        if datetime
+          [false, datetime]
+        else
+          [true, nil]
+        end
+      end
+    end
+
+    def parse_range
+      if x = parse_date_time(nil)
+        from_is_date, from = x
+        to_is_date, to = parse_date_time(from)
+
+        if to
+          if to_is_date
+            Interval.new(from.to_time, to.to_time + 1.day)
+          else
+            Interval.new(from.to_time, to.to_time)
+          end
+        else
+          if from_is_date
+            Interval.new(from.to_time, from.to_time + 1.day)
+          else
+            Event.new(from.to_time)
+          end
+        end
+      end
+    end
+
+    def input_from_offset
+      self.input[self.offset..-1]
+    end
+
+    def peek_time(relative_to)
+      m = self.input_from_offset.match(TIME_REGEX)
+      if m
+        parsed =
+          relative_to.with(
+            hours: m[1].to_i,
+            minutes: m[2].to_i,
+            seconds: 0,
+            zone: @context.timezone,
+          )
+
+        [parsed, *m.offset(0)]
+      end
+    end
+
+    attr_reader :input
+    attr_accessor :offset
+  end
+
+  matcher(:yesterday, /yesterday/) do |m|
+    today = at.to_date
+    yesterday = today - 1
+
+    Interval.new(
+      SniffedTime
+        .from_datetime(yesterday.to_datetime, timezone)
+        .to_time,
+      SniffedTime
+        .from_datetime(today.to_datetime, timezone)
+        .to_time,
+    )
+  end
+
+  matcher(:tomorrow, /tomorrow/i) do |_|
+    tomorrow = at.to_date + 1
+    the_day_after_tomorrow = tomorrow + 1
+
+    Interval.new(
+      SniffedTime
+        .from_datetime(tomorrow.to_datetime, timezone)
+        .to_time,
+      SniffedTime
+        .from_datetime(the_day_after_tomorrow.to_datetime, timezone)
+        .to_time,
+    )
+  end
+
+  TIME_REGEX = /(\d{1,2}):(\d{2})/
+
+  matcher(:time, TIME_REGEX) do |m|
+    times = input.scan(TIME_REGEX).to_a
+    from, to = times[0..2]
+    if to
+      Interval.new(
+        SniffedTime.new(
+          year: at.year,
+          month: at.month,
+          day: at.day,
+          hours: from[0].to_i,
+          minutes: from[1].to_i,
+          seconds: 0,
+          zone: timezone,
+        ).to_time,
+        SniffedTime.new(
+          year: at.year,
+          month: at.month,
+          day: at.day,
+          hours: to[0].to_i,
+          minutes: to[1].to_i,
+          seconds: 0,
+          zone: timezone,
+        ).to_time,
+      )
+    else
+      Event.new(
+        SniffedTime.new(
+          year: at.year,
+          month: at.month,
+          day: at.day,
+          hours: from[0].to_i,
+          minutes: from[1].to_i,
+          seconds: 0,
+          zone: timezone,
+        ).to_time
+      )
+    end
+  end
+
+  DATE_SEPARATOR = /[-\/]/
+  DATE_REGEX = /(\d{1,2})#{DATE_SEPARATOR}(\d{1,2})#{DATE_SEPARATOR}(\d{2,4})/
+
+  matcher(:date, DATE_REGEX) do |m|
+    Parser.new(input, @context).parse_range
+  end
+
+  def initialize(input, at: DateTime.now, timezone:, date_order:, matchers:, raise_errors: false)
+    @input = input
+    @at = at
+    @timezone = timezone
+    @date_order = date_order
+    @context = Context.new(@at, @timezone, @date_order)
+    @matchers = matchers
+    @raise_errors = raise_errors
+  end
+
+  def sniff
+    @matchers.each do |matcher_name|
+      matcher = self.class.matchers[matcher_name]
+      regex, blk = matcher.values_at(:regex, :blk)
+
+      match = regex.match(@input)
+      if match
+        begin
+          result = instance_exec(match, &blk)
+        rescue Exception => e
+          raise if @raise_errors
+        else
+          return result if result
+        end
+      end
+    end
+
+    nil
+  end
+
+  private
+
+  attr_reader :input
+  attr_reader :at
+  attr_reader :timezone
+  attr_reader :date_order
+end
diff --git a/plugin.rb b/plugin.rb
index 8f36ded0..5073d980 100644
--- a/plugin.rb
+++ b/plugin.rb
@@ -3,7 +3,7 @@
 # name: discourse-calendar
 # about: Display a calendar in the first post of a topic
 # version: 0.2
-# author: Joffrey Jaffeux
+# author: Daniel Waterworth, Joffrey Jaffeux
 # url: https://github.com/discourse/discourse-calendar
 
 gem "holidays", "8.0.0", require: false
@@ -14,10 +14,15 @@ enabled_site_setting :calendar_enabled
 
 register_asset "stylesheets/vendor/fullcalendar.min.css"
 register_asset "stylesheets/common/discourse-calendar.scss"
+register_asset "stylesheets/common/post-event.scss"
 register_asset "stylesheets/mobile/discourse-calendar.scss", :mobile
 register_asset "stylesheets/desktop/discourse-calendar.scss", :desktop
+register_svg_icon "fas fa-calendar-day"
+register_svg_icon "fas fa-question"
+register_svg_icon "fas fa-clock"
 
 after_initialize do
+
   module ::DiscourseCalendar
     PLUGIN_NAME ||= "discourse-calendar"
 
@@ -43,18 +48,32 @@ after_initialize do
     def self.users_on_holiday=(usernames)
       PluginStore.set(PLUGIN_NAME, USERS_ON_HOLIDAY_KEY, usernames)
     end
+
+    class Engine < ::Rails::Engine
+      engine_name PLUGIN_NAME
+      isolate_namespace DiscourseCalendar
+    end
   end
 
   [
     "../app/models/calendar_event.rb",
+    "../app/models/guardian.rb",
     "../app/serializers/user_timezone_serializer.rb",
+    "../app/controllers/discourse_calendar/invitees_controller.rb",
+    "../app/controllers/discourse_calendar/post_events_controller.rb",
+    "../app/controllers/discourse_calendar/upcoming_events_controller.rb",
+    "../app/models/discourse_calendar/post_event.rb",
+    "../app/models/discourse_calendar/invitee.rb",
+    "../app/serializers/discourse_calendar/invitee_serializer.rb",
+    "../app/serializers/discourse_calendar/post_event_serializer.rb",
     "../jobs/scheduled/create_holiday_events.rb",
     "../jobs/scheduled/destroy_past_events.rb",
     "../jobs/scheduled/update_holiday_usernames.rb",
     "../lib/calendar_validator.rb",
     "../lib/calendar.rb",
     "../lib/event_validator.rb",
-    "../lib/group_timezones.rb"
+    "../lib/group_timezones.rb",
+    "../lib/time_sniffer.rb",
   ].each { |path| load File.expand_path(path, __FILE__) }
 
   register_post_custom_field_type(DiscourseCalendar::CALENDAR_CUSTOM_FIELD, :string)
@@ -198,4 +217,102 @@ after_initialize do
   add_to_serializer(:site, :include_users_on_holiday?) do
     scope.is_staff?
   end
+
+  require 'post'
+  class ::Post
+    has_one :post_event,
+      dependent: :destroy,
+      class_name: 'DiscourseCalendar::PostEvent',
+      foreign_key: :id
+  end
+
+  add_to_serializer(:post, :post_event) do
+    DiscourseCalendar::PostEventSerializer.new(object.post_event, scope: scope, root: false)
+  end
+
+  reloadable_patch do |plugin|
+    add_to_serializer(:post, :include_post_event?) do
+      plugin.enabled?
+    end
+  end
+
+  Discourse::Application.routes.append do
+    mount ::DiscourseCalendar::Engine, at: '/'
+  end
+
+  DiscourseCalendar::Engine.routes.draw do
+    get '/discourse-calendar/post-events/:id' => 'post_events#show'
+    delete '/discourse-calendar/post-events/:id' => 'post_events#destroy'
+    get '/discourse-calendar/post-events' => 'post_events#index'
+    post '/discourse-calendar/post-events' => 'post_events#create'
+    put '/discourse-calendar/post-events/:id' => 'post_events#update'
+    put '/discourse-calendar/invitees/:id' => 'invitees#update'
+    post '/discourse-calendar/invitees' => 'invitees#create'
+    get '/discourse-calendar/invitees' => 'invitees#index'
+    get '/upcoming-events' => 'upcoming_events#index'
+  end
+
+  DiscourseEvent.on(:post_destroyed) do |post|
+    if post.post_event
+      post.post_event.update!(deleted_at: Time.now)
+    end
+  end
+
+  DiscourseEvent.on(:post_recovered) do |post|
+    if post.post_event
+      post.post_event.update!(deleted_at: nil)
+    end
+  end
+
+  DiscourseEvent.on(:post_edited) do |post, topic_changed|
+    if post.post_event && post.is_first_post? && post.topic && topic_changed && post.topic != Archetype.private_message
+      time_range = extract_time_range(post.topic, post.user)
+
+      case time_range
+      when TimeSniffer::Interval
+        post.post_event.update!(
+          starts_at: time_range.from.to_time.utc,
+          ends_at: time_range.to.to_time.utc,
+        )
+      when TimeSniffer::Event
+        post.post_event.update!(
+          starts_at: time_range.at.to_time.utc
+        )
+      end
+
+      post.post_event.publish_update!
+    end
+  end
+
+  def extract_time_range(topic, user)
+    TimeSniffer.new(
+      topic.title,
+      at: topic.created_at,
+      timezone: user.user_option.timezone || 'UTC',
+      date_order: :sane,
+      matchers: [:tomorrow, :date, :time],
+    ).sniff
+  end
+
+  DiscourseEvent.on(:topic_created) do |topic, args, user|
+    if topic.archetype != Archetype.private_message
+      time_range = extract_time_range(topic, user)
+
+      case time_range
+      when TimeSniffer::Interval
+        DiscourseCalendar::PostEvent.create!(
+          id: topic.first_post.id,
+          starts_at: time_range.from.to_time.utc,
+          ends_at: time_range.to.to_time.utc,
+          status: DiscourseCalendar::PostEvent.statuses[:standalone]
+        )
+      when TimeSniffer::Event
+        DiscourseCalendar::PostEvent.create!(
+          id: topic.first_post.id,
+          starts_at: time_range.at.to_time.utc,
+          status: DiscourseCalendar::PostEvent.statuses[:standalone]
+        )
+      end
+    end
+  end
 end
diff --git a/spec/acceptance/post_spec.rb b/spec/acceptance/post_spec.rb
new file mode 100644
index 00000000..7473c285
--- /dev/null
+++ b/spec/acceptance/post_spec.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+require_relative '../fabricators/post_event_fabricator'
+
+describe Post do
+  PostEvent ||= DiscourseCalendar::PostEvent
+
+  fab!(:user) { Fabricate(:user) }
+  fab!(:topic) { Fabricate(:topic, user: user) }
+  fab!(:post1) { Fabricate(:post, topic: topic) }
+  fab!(:post_event) { Fabricate(:post_event, post: post1) }
+
+  before do
+    freeze_time
+    SiteSetting.queue_jobs = false
+  end
+
+  context 'when a post with an event is destroyed' do
+    it 'sets deleted_at on the post_event' do
+      expect(post_event.deleted_at).to be_nil
+
+      PostDestroyer.new(user, post_event.post).destroy
+      post_event.reload
+
+      expect(post_event.deleted_at).to eq(Time.now)
+    end
+  end
+
+  context 'when a post with an event is recovered' do
+    it 'nullifies deleted_at on the post_event' do
+      PostDestroyer.new(user, post_event.post).destroy
+      post_event.reload
+
+      expect(post_event.deleted_at).to eq(Time.now)
+
+      PostDestroyer.new(user, post_event.post).recover
+      post_event.reload
+
+      expect(post_event.deleted_at).to be_nil
+    end
+  end
+end
diff --git a/spec/acceptance/topic_spec.rb b/spec/acceptance/topic_spec.rb
new file mode 100644
index 00000000..9eb4c3f5
--- /dev/null
+++ b/spec/acceptance/topic_spec.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe Topic do
+  PostEvent ||= DiscourseCalendar::PostEvent
+
+  before do
+    freeze_time
+    SiteSetting.queue_jobs = false
+  end
+
+  fab!(:user) { Fabricate(:user) }
+
+  context 'when a topic is created' do
+    context 'with a date' do
+      it 'creates a post event' do
+        post_with_date = PostCreator.create!(
+          user,
+          title: 'Let’s buy a boat with me tomorrow',
+          raw: 'The boat market is quite active lately.'
+        )
+
+        post_event = PostEvent.find(post_with_date.id)
+        expect(post_event).to be_present
+        expect(post_event.starts_at).to eq(post_with_date.topic.created_at.tomorrow.beginning_of_day)
+        expect(post_event.status).to eq(PostEvent.statuses[:standalone])
+      end
+    end
+  end
+end
diff --git a/spec/fabricators/post_event_fabricator.rb b/spec/fabricators/post_event_fabricator.rb
new file mode 100644
index 00000000..637f8f05
--- /dev/null
+++ b/spec/fabricators/post_event_fabricator.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+Fabricator(:post_event, from: 'DiscourseCalendar::PostEvent') do
+  post { |attrs| attrs[:post] }
+
+  id { |attrs| attrs[:post].id }
+
+  status { |attrs|
+    attrs[:status] ?
+    DiscourseCalendar::PostEvent.statuses[attrs[:status]] :
+    DiscourseCalendar::PostEvent.statuses[:public]
+  }
+  starts_at { |attrs| attrs[:starts_at] || 1.day.from_now.iso8601 }
+  ends_at { |attrs| attrs[:ends_at] }
+end
diff --git a/spec/lib/time_sniffer_spec.rb b/spec/lib/time_sniffer_spec.rb
new file mode 100644
index 00000000..1f81a0f4
--- /dev/null
+++ b/spec/lib/time_sniffer_spec.rb
@@ -0,0 +1,211 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe TimeSniffer do
+  before do
+    freeze_time DateTime.parse('2020-04-24 14:10')
+  end
+
+  let(:default_context) {
+    {
+      at: DateTime.parse('2020-1-20 00:00:00'),
+      timezone: 'EST',
+      date_order: :sane,
+      matchers: [:tomorrow, :date, :time],
+      raise_errors: true,
+    }
+  }
+
+  define_method(:expect_parsed_as_interval) do |str, from:, to:, context: default_context|
+    Time.use_zone(context[:timezone]) do
+      expect(TimeSniffer.new(str, **context).sniff).to(
+        eq(TimeSniffer::Interval.new(Time.zone.parse(from), Time.zone.parse(to)))
+      )
+    end
+  end
+
+  define_method(:expect_parsed_as_event) do |str, at, context: default_context|
+    Time.use_zone(context[:timezone]) do
+      expect(TimeSniffer.new(str, **context).sniff).to(
+        eq(TimeSniffer::Event.new(Time.zone.parse(at)))
+      )
+    end
+  end
+
+  define_method(:expect_parsed_as_nil) do |str, context: default_context|
+    expect(TimeSniffer.new(str, **context).sniff).to(
+      eq(nil)
+    )
+  end
+
+  it "should support tomorrow with a timezone" do
+    expect_parsed_as_interval(
+      "tomorrow",
+      from: "2020-1-21 EST",
+      to: "2020-1-22 EST",
+    )
+  end
+
+  it "should support Tomorrow" do
+    expect_parsed_as_interval(
+      "Tomorrow",
+      from: "2020-1-21",
+      to: "2020-1-22",
+    )
+  end
+
+  it "should support 14:00" do
+    expect_parsed_as_event("14:00", "2020-1-20 14:00 EST")
+  end
+
+  it "should support 14:24" do
+    expect_parsed_as_event("14:24", "2020-1-20 14:24 EST")
+  end
+
+  it "should support 15:00 with emojis" do
+    expect_parsed_as_event("😊😊😊😊15:00😊😊😊😊", "2020-1-20 15:00 EST")
+  end
+
+  it "should support 14:00 - 15:00" do
+    expect_parsed_as_interval(
+      "14:00 - 15:00",
+      from: "2020-1-20 14:00 EST",
+      to: "2020-1-20 15:00 EST",
+    )
+  end
+
+  it "should support too many times" do
+    expect_parsed_as_interval(
+      "14:00 - 15:00 asotuhosthu 16:00",
+      from: "2020-1-20 14:00 EST",
+      to: "2020-1-20 15:00 EST",
+    )
+  end
+
+  it "should support too many times" do
+    expect_parsed_as_interval(
+      "14:00 - 15:00 asotuhosthu 16:00",
+      from: "2020-1-20 14:00 EST",
+      to: "2020-1-20 15:00 EST",
+    )
+  end
+
+  it "should support a date" do
+    expect_parsed_as_interval(
+      "31/3/25",
+      from: "2025-3-31 00:00 EST",
+      to: "2025-4-1 00:00 EST",
+    )
+  end
+
+  it "should support a date in the past century" do
+    expect_parsed_as_interval(
+      "31/3/75",
+      from: "1975-3-31 00:00 EST",
+      to: "1975-4-1 00:00 EST",
+    )
+  end
+
+  it "should support a date with a year with 4 digits" do
+    expect_parsed_as_interval(
+      "31/3/2021",
+      from: "2021-3-31 00:00 EST",
+      to: "2021-4-1 00:00 EST",
+    )
+  end
+
+  it "should support a date with hyphens" do
+    expect_parsed_as_interval(
+      "31-3-25",
+      from: "2025-3-31 00:00 EST",
+      to: "2025-4-1 00:00 EST",
+    )
+  end
+
+  it "should support a date with a time" do
+    expect_parsed_as_event(
+      "31-3-25 08:00",
+      "2025-3-31 08:00 EST",
+    )
+  end
+
+  it "should support a date with a time with non-zero minutes" do
+    expect_parsed_as_event(
+      "31-3-25 08:45",
+      "2025-3-31 08:45 EST",
+    )
+  end
+
+  it "should support a date with a time and a timezone" do
+    expect_parsed_as_event(
+      "31-3-25 08:00 UTC",
+      "2025-3-31 08:00:00 UTC",
+      context: default_context.merge(timezone: 'EST'),
+    )
+  end
+
+  it "should support a date with a time and a timezone" do
+    expect_parsed_as_event(
+      "31-3-25 08:00UTC",
+      "2025-3-31 08:00:00 UTC",
+      context: default_context.merge(timezone: 'EST'),
+    )
+  end
+
+  it "should support a date with a time and a timezone" do
+    expect_parsed_as_event(
+      "31-3-25 08:00Z",
+      "2025-3-31 08:00:00 UTC",
+      context: default_context.merge(timezone: 'EST'),
+    )
+  end
+
+  it "should support a date range" do
+    expect_parsed_as_interval(
+      "25/2/21 - 10/3/22",
+      from: "2021-2-25 00:00 EST",
+      to: "2022-3-11 00:00 EST",
+    )
+  end
+
+  it "should support a date range" do
+    expect_parsed_as_interval(
+      "25/2/21 - 10/3/22 14:00",
+      from: "2021-2-25 00:00 EST",
+      to: "2022-3-10 14:00 EST",
+    )
+  end
+
+  it "should support a date range with two times" do
+    expect_parsed_as_interval(
+      "25/2/21 9:00 - 10/3/22 14:00",
+      from: "2021-2-25 09:00 EST",
+      to: "2022-3-10 14:00 EST",
+    )
+  end
+
+  it "should support a date range with two times where the second is relative to the first" do
+    expect_parsed_as_interval(
+      "25/2/21 9:00 - 14:00",
+      from: "2021-2-25 09:00 EST",
+      to: "2021-2-25 14:00 EST",
+    )
+  end
+
+  it "should correctly handle timezones in future" do
+    expect_parsed_as_event(
+      "24/06/2020 14:23",
+      "2020-06-24 14:23 CEST",
+      context: default_context.merge(timezone: 'Europe/Paris'),
+    )
+  end
+
+  it "should not find a time in a random number" do
+    expect_parsed_as_nil("1500")
+  end
+
+  it "should not find a time in random numbers and an emoji" do
+    expect_parsed_as_nil("15😊00")
+  end
+end
diff --git a/spec/requests/invitees_controller_spec.rb b/spec/requests/invitees_controller_spec.rb
new file mode 100644
index 00000000..82a0fa61
--- /dev/null
+++ b/spec/requests/invitees_controller_spec.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+require_relative '../fabricators/post_event_fabricator'
+
+module DiscourseCalendar
+  describe InviteesController do
+    fab!(:user) { Fabricate(:user, admin: true) }
+    fab!(:topic) { Fabricate(:topic, user: user) }
+    fab!(:post1) { Fabricate(:post, user: user, topic: topic) }
+
+    before do
+      SiteSetting.queue_jobs = false
+      sign_in(user)
+    end
+
+    context 'when a post event exists' do
+      context 'when an invitee exists' do
+        fab!(:invitee1) { Fabricate(:user) }
+        fab!(:post_event) {
+          pe = Fabricate(:post_event, post: post1)
+          pe.create_invitees([{
+            user_id: invitee1.id,
+            status: Invitee.statuses[:going]
+          }])
+          pe
+        }
+
+        it 'updates its status' do
+          invitee = post_event.invitees.first
+
+          expect(invitee.status).to eq(0)
+
+          put "/discourse-calendar/invitees/#{invitee.id}.json", params: {
+            invitee: {
+              status: "interested"
+            }
+          }
+
+          invitee.reload
+
+          expect(invitee.status).to eq(1)
+        end
+      end
+
+      context 'when an invitee doesn’t exist' do
+        fab!(:post_event) { Fabricate(:post_event, post: post1) }
+
+        it 'creates an invitee' do
+          post "/discourse-calendar/invitees.json", params: {
+            invitee: {
+              user_id: user.id,
+              post_id: post_event.id,
+              status: "not_going",
+            }
+          }
+
+          expect(Invitee).to exist(
+            post_id: post_event.id,
+            user_id: user.id,
+            status: 2,
+          )
+        end
+      end
+    end
+  end
+end
diff --git a/spec/requests/post_events_controller_spec.rb b/spec/requests/post_events_controller_spec.rb
new file mode 100644
index 00000000..9726cf32
--- /dev/null
+++ b/spec/requests/post_events_controller_spec.rb
@@ -0,0 +1,328 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+require_relative '../fabricators/post_event_fabricator'
+
+module DiscourseCalendar
+  describe PostEventsController do
+    fab!(:user) { Fabricate(:user, admin: true) }
+    fab!(:topic) { Fabricate(:topic, user: user) }
+    fab!(:post1) { Fabricate(:post, user: user, topic: topic) }
+    fab!(:invitee1) { Fabricate(:user) }
+    fab!(:invitee2) { Fabricate(:user) }
+
+    before do
+      SiteSetting.queue_jobs = false
+      SiteSetting.displayed_invitees_limit = 3
+    end
+
+    context 'when a post exists' do
+      fab!(:invitee3) { Fabricate(:user) }
+      fab!(:invitee4) { Fabricate(:user) }
+      fab!(:invitee5) { Fabricate(:user) }
+      fab!(:group) {
+        Fabricate(:group).tap do |g|
+          g.add(invitee2)
+          g.add(invitee3)
+          g.save!
+        end
+      }
+
+      before do
+        sign_in(user)
+      end
+
+      it 'creates a post event' do
+        post '/discourse-calendar/post-events.json', params: {
+          post_event: {
+            id: post1.id
+          }
+        }
+
+        expect(response.status).to eq(200)
+        json = ::JSON.parse(response.body)
+        expect(json['post_event']['id']).to eq(post1.id)
+        expect(PostEvent).to exist(id: post1.id)
+      end
+
+      it 'accepts user and group invitees' do
+        invitees = [invitee1.username, group.name]
+
+        post '/discourse-calendar/post-events.json', params: {
+          post_event: {
+            id: post1.id,
+            raw_invitees: invitees,
+            status: PostEvent.statuses[:private],
+            display_invitees: PostEvent.display_invitees_options[:everyone]
+          }
+        }
+
+        expect(response.status).to eq(200)
+        json = ::JSON.parse(response.body)
+        sample_invitees = json['post_event']['sample_invitees']
+        expect(sample_invitees.map { |i| i['user']['id'] }).to match_array([user.id, invitee1.id, group.group_users.first.user.id])
+        raw_invitees = json['post_event']['raw_invitees']
+        expect(raw_invitees).to match_array(invitees)
+      end
+
+      it 'accepts one user invitee' do
+        post '/discourse-calendar/post-events.json', params: {
+          post_event: {
+            id: post1.id,
+            status: PostEvent.statuses[:private],
+            raw_invitees: [invitee1.username],
+          }
+        }
+
+        expect(response.status).to eq(200)
+        json = ::JSON.parse(response.body)
+        sample_invitees = json['post_event']['sample_invitees']
+        expect(sample_invitees[0]['user']['username']).to eq(user.username)
+        expect(sample_invitees[1]['user']['username']).to eq(invitee1.username)
+      end
+
+      it 'accepts one group invitee' do
+        post '/discourse-calendar/post-events.json', params: {
+          post_event: {
+            id: post1.id,
+            status: PostEvent.statuses[:private],
+            raw_invitees: [group.name],
+          }
+        }
+
+        expect(response.status).to eq(200)
+        json = ::JSON.parse(response.body)
+        sample_invitees = json['post_event']['sample_invitees']
+        expect(sample_invitees.map { |i| i['user']['username'] }).to match_array([user.username] + group.group_users.map(&:user).map(&:username))
+      end
+
+      it 'accepts no invitee' do
+        post '/discourse-calendar/post-events.json', params: {
+          post_event: {
+            id: post1.id,
+            raw_invitees: [],
+            status: PostEvent.statuses[:private],
+            display_invitees: PostEvent.display_invitees_options[:everyone]
+          }
+        }
+
+        expect(response.status).to eq(200)
+        json = ::JSON.parse(response.body)
+        sample_invitees = json['post_event']['sample_invitees']
+        expect(sample_invitees.count).to eq(1)
+        expect(sample_invitees[0]['user']['username']).to eq(user.username)
+      end
+
+      it 'limits displayed invitees' do
+        post '/discourse-calendar/post-events.json', params: {
+          post_event: {
+            id: post1.id,
+            status: PostEvent.statuses[:private],
+            raw_invitees: [
+              invitee1.username,
+              invitee2.username,
+              invitee3.username,
+              invitee4.username,
+              invitee5.username,
+            ],
+          }
+        }
+
+        expect(response.status).to eq(200)
+        json = ::JSON.parse(response.body)
+        sample_invitees = json['post_event']['sample_invitees']
+        expect(sample_invitees.map { |i| i['user']['username'] }).to match_array([user.username, invitee1.username, invitee2.username])
+      end
+
+      context 'when a post_event exists' do
+        fab!(:post_event) { Fabricate(:post_event, post: post1) }
+
+        context 'when we update the post_event' do
+          context 'when status changes from standalone to private' do
+            it 'changes the status, raw_invitees and invitees' do
+              post_event.update!(status: PostEvent.statuses[:standalone])
+
+              put "/discourse-calendar/post-events/#{post_event.id}.json", params: {
+                post_event: {
+                  status: PostEvent.statuses[:private].to_s,
+                  raw_invitees: [invitee1.username]
+                }
+              }
+
+              post_event.reload
+
+              expect(post_event.status).to eq(PostEvent.statuses[:private])
+              expect(post_event.raw_invitees).to eq([invitee1.username])
+              expect(post_event.invitees.pluck(:user_id)).to match_array([invitee1.id])
+            end
+          end
+
+          context 'when status changes from standalone to public' do
+            it 'changes the status' do
+              post_event.update!(status: PostEvent.statuses[:standalone])
+
+              put "/discourse-calendar/post-events/#{post_event.id}.json", params: {
+                post_event: {
+                  status: PostEvent.statuses[:public].to_s
+                }
+              }
+
+              post_event.reload
+
+              expect(post_event.status).to eq(PostEvent.statuses[:public])
+              expect(post_event.raw_invitees).to eq([])
+              expect(post_event.invitees).to eq([])
+            end
+          end
+
+          context 'when status changes from private to standalone' do
+            it 'changes the status' do
+              post_event.update!(
+                status: PostEvent.statuses[:private],
+                raw_invitees: [invitee1.username]
+              )
+              post_event.fill_invitees!
+
+              post_event.reload
+
+              expect(post_event.invitees.pluck(:user_id)).to eq([invitee1.id])
+              expect(post_event.raw_invitees).to eq([invitee1.username])
+
+              put "/discourse-calendar/post-events/#{post_event.id}.json", params: {
+                post_event: {
+                  status: PostEvent.statuses[:standalone].to_s
+                }
+              }
+
+              post_event.reload
+
+              expect(post_event.status).to eq(PostEvent.statuses[:standalone])
+              expect(post_event.raw_invitees).to eq([])
+              expect(post_event.invitees).to eq([])
+            end
+          end
+
+          context 'when status changes from private to public' do
+            it 'changes the status, removes raw_invitees and keeps invitees' do
+              post_event.update!(
+                status: PostEvent.statuses[:private],
+                raw_invitees: [invitee1.username]
+              )
+              post_event.fill_invitees!
+
+              post_event.reload
+
+              expect(post_event.invitees.pluck(:user_id)).to eq([invitee1.id])
+              expect(post_event.raw_invitees).to eq([invitee1.username])
+
+              put "/discourse-calendar/post-events/#{post_event.id}.json", params: {
+                post_event: {
+                  status: PostEvent.statuses[:public].to_s
+                }
+              }
+
+              post_event.reload
+
+              expect(post_event.status).to eq(PostEvent.statuses[:public])
+              expect(post_event.raw_invitees).to eq([])
+              expect(post_event.invitees.pluck(:user_id)).to eq([invitee1.id])
+            end
+          end
+
+          context 'when status changes from public to private' do
+            it 'changes the status, removes raw_invitees and keeps invitees' do
+              post_event.update!(status: PostEvent.statuses[:public])
+              post_event.create_invitees([
+                { user_id: invitee1.id },
+                { user_id: invitee2.id },
+              ])
+              post_event.reload
+
+              expect(post_event.invitees.pluck(:user_id)).to match_array([invitee1.id, invitee2.id])
+              expect(post_event.raw_invitees).to eq(nil)
+
+              put "/discourse-calendar/post-events/#{post_event.id}.json", params: {
+                post_event: {
+                  status: PostEvent.statuses[:private].to_s,
+                  raw_invitees: [invitee1.username]
+                }
+              }
+
+              post_event.reload
+
+              expect(post_event.status).to eq(PostEvent.statuses[:private])
+              expect(post_event.raw_invitees).to eq([invitee1.username])
+              expect(post_event.invitees.pluck(:user_id)).to eq([invitee1.id])
+            end
+          end
+
+          context 'when status changes from public to standalone' do
+            it 'changes the status, removes invitees' do
+              post_event.update!(
+                status: PostEvent.statuses[:public]
+              )
+              post_event.create_invitees([ { user_id: invitee1.id } ])
+              post_event.reload
+
+              expect(post_event.invitees.pluck(:user_id)).to eq([invitee1.id])
+              expect(post_event.raw_invitees).to eq(nil)
+
+              put "/discourse-calendar/post-events/#{post_event.id}.json", params: {
+                post_event: {
+                  status: PostEvent.statuses[:standalone].to_s
+                }
+              }
+
+              post_event.reload
+
+              expect(post_event.status).to eq(PostEvent.statuses[:standalone])
+              expect(post_event.raw_invitees).to eq([])
+              expect(post_event.invitees).to eq([])
+            end
+          end
+        end
+
+        context 'acting user has created the post_event' do
+          it 'destroys a post_event' do
+            expect(post_event.persisted?).to be(true)
+
+            messages = MessageBus.track_publish do
+              delete "/discourse-calendar/post-events/#{post_event.id}.json"
+            end
+            expect(messages.count).to eq(1)
+            message = messages.first
+            expect(message.channel).to eq("/post-events/#{post_event.post.topic_id}")
+            expect(message.data[:id]).to eq(post_event.id)
+            expect(response.status).to eq(200)
+            expect(PostEvent).to_not exist(id: post_event.id)
+          end
+        end
+
+        context 'acting user has not created the post_event' do
+          fab!(:lurker) { Fabricate(:user) }
+
+          before do
+            sign_in(lurker)
+          end
+
+          it 'doesn’t destroy the post_event' do
+            expect(post_event.persisted?).to be(true)
+            delete "/discourse-calendar/post-events/#{post_event.id}.json"
+            expect(response.status).to eq(403)
+            expect(PostEvent).to exist(id: post_event.id)
+          end
+
+          it 'doesn’t update the post_event' do
+            put "/discourse-calendar/post-events/#{post_event.id}.json", params: {
+              post_event: {
+                status: PostEvent.statuses[:public],
+              }
+            }
+
+            expect(response.status).to eq(403)
+          end
+        end
+      end
+    end
+  end
+end