I'm actually about to make a dip into using Backbone so I've been holding off on transitioning to CoffeeScript to limit my shock.
I've played around with the editor at GitHub though and I really like how CoffeeScript reads. That being said, actually using it in the wild seems is road I'm not quite ready to cross yet.
I've started using Backbone.js in a very limited way for some of our existing apps.
What I'm doing is just using views as a way to provide some structure to what is currently a mess of jQuery event bindings and DOM manipulation. So instead of have a Backbone view that gets configured with a template and passed a model to render, I just do some setup code in the initialize function and then use Backbone's event function to setup all my event bindings for different DOM events that will occur within the element that is the root of that particular view.
This is working really well so far. It doesn't require completely rewriting the app to be a single-page client side heavy application, but does provide a significant amount of structure to the code making it much more manageable. It also lets me reuse some views (sort of like widgets) that were previously tied directly to specific elements in the DOM.
I've played around with the editor at GitHub though and I really like how CoffeeScript reads. That being said, actually using it in the wild seems is road I'm not quite ready to cross yet.