At
paperbackswap.com , you post books you're done with, send them off to people who want them, and get credits to demand books you want from other people. I signed up a few weeks ago, sent off a round of books, thought "aw, this was a lame hassle; whatever," and forgot about it until one of the books on my wishlist showed up: Chez Panisse Pasta, Pizza and Calzone (in hardcover, no less).
I just got it in the mail today and now I'm way into this game again. I have three more on the way, two of which are audiobooks. Super fun, and the only entity you have to pay is the post office. Anyone else tried it?