Due to budget cuts, our library has a huge collection of children's paperbacks that are on the "honor system". Rivka is addicted to The Magic Treehouse series at the moment, and there's like a bazillion of them. The books are all clearly labeled with bright yellow stickers, and you just bring them back when you're done, or risk angering the Library Gods, who will send you bad juju for abusing the system. We take it very seriously around here.