I discovered this eco-charity today, and I think it's pretty cool. I'm considering making it one of my "official" charities.* Basically, they plant a tree for every dollar you donate, and they send you a little sticker for your book.
I'm really happy to see something like this. I'd never thought about the deforestation my reading habit causes. I always thought most books involved recycled paper at least. Real food-for-thought for a bibliophile who despises e-books.