New Twiddle

controllers.application.js

import Ember from 'ember';

let i = 0;

export default Ember.Controller.extend({
  foo: function(event) {
    console.log(++i, this, event);
  },
  actions: {
    thing: function(event) {
      // 1. You've passed off the function without the invocation context.
      Ember.run(this.foo);
      // 2. this works.
      Ember.run(() => { this.foo(event) });
      // 3. this works, it is a two step create + invoke thing.
      // Use this when you want to pass the function out of Ember.
      var result = Ember.run.bind(this, this.foo);
      result(event);
    }
  }
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
});

templates.application.hbs

<button onclick={{action 'thing'}}>thing</button>

twiddle.json

{
  "version": "0.11.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.10.2",
    "ember-data": "2.11.0",
    "ember-template-compiler": "2.10.2",
    "ember-testing": "2.10.2"
  },
  "addons": {}
}