I enjoy working on bikes. When I got some fenders to put on my fixed-gear, I found the directions to be unclear, so I collected some information from a mailing list I subscribe to, and wrote up a how-to a la the Linux Documentation Project.
The bike I ride the most is my fixed-gear, an old steel frame from the '70s that I built up with new parts.
My mountain bike is a KHS hardtail.
I've got a Raleigh Sports for around-town stuff, which usually consists of getting coffee at Westside Coffee Company, where I'm learning basic Cantonese phrases from two of the baristas, but that's another story.