Barista is my alternative to bistro_car that aims to make integrating coffeescripts into a rails application painless. It lets you automatically compile any coffeescript under app/coffeescripts in Rails to public/javascripts, meaning your coffeescripts are transparent to the application (for the most part).

More importantly for me, it integrates well with Jammit (you can easily compile all coffeescripts) and it also provides Compass-inspired frameworks, making it easy to package up coffeescript libraries in a reusable manner, making add a library as simple as adding a gem to your Gemfile and running bundle install.