Hobby project, practicing AI, state machines, and puzzle design/implementation.
Hobby HTML5 project, practicing path finding, collision detection, level design and map editor creation, and minimal AI.
Hobby project, because, I really do love MUD's.
Hobby project, wrote a kernel (and minimal CLI) for my Intel PC in C++.
Hobby project, learning OpenGL, shaders, 3D geometry, Quake 3 BSP's, Doom 3's mesh format.
Wrote an elaborate user tracker for MySpace.
Self employment suite that I made to manage my projects, invoices, hours, etc.
Hobby project, a Windows 95/98 calendar that embedded itself on your desktop.