Knockout.js

As I was reading up more of Ember.js (formerly Amber.js / SproutCore 2.0) I stumbled over Knoutout.js, yet another Javascript framework on the client side.
It also looks pretty nice in terms of writing speed and re-usage of certain modules.

Also, they've done a fantastic job for learning Knockout.js over at http://learn.knockoutjs.com/

By the way: Happy new year everyone! See you in 2012.