Not really robot related, but sometimes I get so frustrated with work I need to blow off some steam. Enter Backyard Ballistics, a great book that teaches you how to make spudguns, mini-catapults, and smallest of all, matchstick rockets.
This, and a few more books are written by William Gurstell, the man who had a website called backyard-ballistics.com, that sparked my brain into more research into amateury-ness.