A company called PediaPress is allowing users to turn a collection of Wikipedia pages into softcover books. In theory, this would let you create your own bound volume on any damn thing, as, really, your creativity is the limit. Want to create your own science textbook? You could do that, sure. Want to create a guide for power tools? Just hit those pages up. Want a tome that covers, in detail, ancient meditation techniques and famous clowns? You can do that, too. And so it goes.
A portion of the proceeds from the books you print will go to Wikipedia, to boot. Prices vary depending on how big your book will be (a book simply titled "Wikipedia," for instance, would probably be pretty expensive), though they start at $8.90. If you're really looking for Wikipedia on the go, though, there's already a gadget for that — the WikiReader.
Check out the PediaPress website for a video demonstration if having Wikipedia on the web just isn't good enough for you.