There's probably hundreds of Javascript MVC frameworks out there. But my favorite, Agility.js, seems to be barely ever mentioned. Agility has served me well in several projects both big and small, so I'm writing a tutorial in the spirit of Step by step from jQuery to Backbone for Agility.
What makes Agility different from other MVC frameworks? In short, the lack of boilerplate and the completeness. Other frameworks involve many, many lines of boilerplate that provide a significant barrier to entry and detract from the readability of the final product. Agility minimizes this, lets you get started fast, and stays out of your way. But it doesn't sacrifice either completeness or maintainability. Agility is feature-rich, including two-way model-view bindings, declarative controller-events, prototypical inheritance, server persistance, and everything else