Vex : Vex is a modern dialog library which is highly configurable, easily stylable, and gets out of the way. You'll love vex because it's tiny (6kb minified...
TraceKit : Not all browsers support stack traces on error objects, but TraceKit squeezes out as much useful information as possible and normalizes it.
stream.js : stream.js is a tiny stand-alone Javascript library that unlocks a new data structure for you: streams.
TodoMVC : A project which offers the same Todo application implemented using MV concepts in most of the popular JavaScript MV frameworks of today.
Headroom.js is a lightweight, high-performance JS widget (with no dependencies!) that allows you to react to the user's scroll.