Why's Poignant Guide to Ruby, a gleefully insane and yet surprisingly useful beginner's guide to the Ruby language, peppered with zany examples and illustrated with cartoons, and sidebars rambling about gigantic robot monkey brains and such. A bit like those children's guides to TRS-80 BASIC programming and such that were around in the 1980s, only on much stronger drugs.
Ruby's a fairly nifty language; though probably a bit too overshadowed by both Perl and Python, which are technically more ordinary-looking but good enough for most things and have inertia behind them, to become big. Still, I should probably get around to doing more with it at some stage.