TraceKit : Not all browsers support stack traces on error objects, but TraceKit squeezes out as much useful information as possible and normalizes it.
The HTML5 Shiv : The HTML5 Shiv enables use of HTML5 sectioning elements in legacy Internet Explorer and provides basic HTML5 styling for Internet Explorer 6-9, Safari...
jsfx : This is a javascript library (with frontend) for sound effect generation.
JavascriptOO : Every javascript project you should be looking into.
With examples, categories, install commands, CDN links, project and author stats, and more.
RequireJS : RequireJS is a JavaScript file and module loader. It is optimized for in-browser use, but it can be used in other JavaScript environments, like Rhino ...
A simple library for handling keyboard shortcuts in Javascript.