Wikibooks I contribute to:
- MySQL: a completely free-as-in-freedom documentation on the popular SGBD.
- Blender 3D: Noob to Pro: great tutorials to learn this 3D modeling / animation / texturing / etc. environment.
- OpenGL_Programming: adding how to use OpenGL the 2.x aka "modern" way.
Wikibooks I like:
- Lucid Dreaming: I should take the time to read it entirely :)