I'm quite certain that I'm chemically addicted to exercise. Basketball and cycling make up the majority of it, though I've started trail running as well. We'll see if that keeps up. Also, I just ran my first 5K in 26:06 and then kept going to complete a 30 minute run (Sept 14, '05). (5k in 22:43 on Feb 17, '06)
I own a 2005 Giant OCR Touring bike that was kind enough to carry me over some mountains in France. The Virtual Alps really helped get my appetite going for the trip. I'm really an amateur though. Park Tools and Sheldon Brown both have great resources on bike maintenance. However, I'm a fairly poor mechanic.