The Dojo Toolkit : Dojo saves you time and scales with your development process, using web standards as its platform. It’s the toolkit experienced developers turn to for...
Sammy.js : Sammy is a tiny javascript framework built on top of jQuery, It's RESTful Evented Javascript.
InstantClick : InstantClick is a JavaScript library that dramatically speeds up your website, making navigation effectively instant in most cases.
Add Clippy or his friends to any website for instant nostalgia.