Version 2.0 of the Playbook, which was just released, has webGL on in the browser. Excellent!
A port of the Chipmunk-physics game engine to JavaScript, for games and other applications.
Ryan LeFevre has been working on psd.js, which is as you might have already guessed, is a Photoshop Document parser that works in both the browser and Node.js.
psd.js is a general purpose file parser for PSD files created in Photoshop. Given a PSD file, it can parse out information such as…
zip.js offers a low-level API for writing and reading large zip files (up to 4GB) with a stable RAM use. It also offers a Filesystem API in order to manipulate zip file structure.
(Source: gildas-lormeau.github.com)
HTML5 Games: Creating Fun with HTML5, CSS3, and WebGL (via Amazon.com: HTML5 Games: Creating Fun with HTML5, CSS3, and WebGL (9781119975083): Jacob Seidelin: Books)