Oh boy! I can't remember the last time I was so excited about a web site. (Maybe it was 43 Things.)Thanks to Claire - I have fallen in love with BookMooch. It's a book trading site wherein you create an inventory, gaining 1/10 of a point for each book you include. Then you get points (3 if you're sending internationally) for books you agree to send out. You are deducted 2 points for each book you have sent to you. Simple, but effective.
The best part is that you're not excluded if you don't happen to live in the States. This afternoon, I off-loaded the disappointing Charmed Thirds to a girl in Hamburg and sent the unspeakably creepy The Killer Inside Me to a guy in Chicago. I'm waiting to get a book about German Shepherds from a person in Nevada and a memoir called Self-Made Man (about a woman who does an anthropological study by passing herself off as a man) from somebody in the UK.
You can make a wishlist and search for books you want to mooch. The site design looks good and works pretty well (although it's a bit slow at times).
It's the perfect site for someone like me who loves books, isn't fussy about used books, and doesn't mind trading in books. Check it out. (You can see my wishlist here - if you promise not to judge me.)