This looks promising:

MochiKit - lightweight Javascript library

MochiKit makes JavaScript suck less

MochiKit is a highly documented and well tested, suite of JavaScript libraries that will help you get sh*t done, fast. We took all the good ideas we could find from our Python, Objective-C, etc.Experiencee and adapted it to the crazy world of JavaScript.

I was also impressed by the web syntax highlighting performed by dp.SyntaxHighlighter.