I've contributed code to a handful, but spend most of my coding time working on Jellybean and, more recently, the Everything Engine.

I started the former 'cuz the notion of a small, fast, and ubiquitous network application framework was too powerful to pass up, and I work on the latter 'cuz it's technically challenging and they pay me money. The other things I've worked on were either written by people I know who asked for my opinion or were cool hacks I wanted to understand better.