Edit in JSFiddle

var App = Ember.Application.create();

App.ApplicationController = Ember.Controller.extend();
App.ApplicationView = Ember.View.extend({
  templateName: 'application'
});

App.Router = Ember.Router.extend({
  root: Ember.Route.extend({
    index: Ember.Route.extend({
      route: '/'
    })
  })
});

App.initialize();

<script type="text/x-handlebars" data-template-name="application">
    <h1>Hello from Ember.js</h1>
</script>