HTML5 libraries - Late June
Some exciting libraries have cropped up lately:
Paper.js - a vector graphics scripting framework that runs on top of
<canvas>. It is based on and largely compatible with Scriptographer, a scripting environment for Adobe Illustrator. If you've ever wanted an object model to sit above canvas, take a peek.
Chop Slider - making heavy use of CSS transitions and effects to get impressive transitions between states.