Edit: previous example was incorrect as pointed out by klibertp below. Hopefully they're correct now...

it's not exactly a shining example of good coffeescript, but I think this is equivalent js

    MyApp.president = Ember.Object.create({
        fullName: function(){
            return this.get('firstName') + ' ' + this.get('lastName');
        }.property('firstName', 'lastName')
    })

I'd probably write it in cs as

    MyApp.president = Ember.Object.create
        fullName: (
            -> "#{@get 'firstName'} #{@get 'lastName'}"
        ).property('firstName', 'lastName')

(ie multi line rather than a single line) but that's very much just stylistic choice. It's also a lousy example of the benefits of cs as the cs version doesn't add any benefit over the plain js one.