One of the first things I missed from the MVC frameworks I had prior experience with before using Backbone was a controller that links up URL routing with controller actions, providing a clean way to organize business logic. BackboneMVC does that.
It also provides beforeFilter, a deferred afterRender, and a mechanism for checking the session for a valid user before granting access to specified controller actions. Pretty neat.
Check out the BackboneMVC homepage for details.