I'm so in love with this new website my girlfriend recommended. You input all the titles of books you own, but would be happy to trade, and then create a wish list of all the books you'd like and the computer gets to work matching you up with people to trade books with! We've been getting a steady stream of new books in the mail ever since I signed up; Sam thinks it's his birthday every day! There's something so satisfying about connecting with other people for a mutually beneficial endeavor. I somehow feel like I'm pulling one over on life, getting great stuff for free. I once attended this really fabulous conference on teaching economics and they did a wonderful activity that demonstrated how free trade increases wealth, which can be a hard concept to grasp since the amount of actual stuff doesn't change, only its value changes (am I boring you? Sorry, I think economics is really fascinating!). I just keep thinking about that principle when I'm trading books I don't really value for books that have a lot of value to me and then, all of a sudden, we're all richer! I own more goodies that are worth more to me, and so does the person who got my books. It's brilliant! And if grooving on economic principles in action doesn't turn you on, how about just getting random surprises in the mail? Everyone loves getting treats in the mail. I've gotten a few books for myself and quite a few picture books for Sam. There are a few books that I repeatedly check out of the library, but have been too stingy to just go out and buy, but I've been able to get them on Swap Tree. Check it out; I think you'll love it!