HTML5 and CSS3 advent calendar 2011 edition.
19 creative computer animations to inspire you.
Interactive CSS3 lighting effects.
HTML5 and CSS3 without guilt.
Animate.css is a bunch of cool, fun, and cross-browser animations for you to use in your projects.
Game Theory 101: Game theory made easy.
An introduction to object oriented CSS (OOCSS).
Learn almost anything for free at Khan Academy.