Via Conor comes the link to BookCrossing, where you register your books and then leave them in some public place for other people to read and log and so on...I was shocked to see that my own Northridge, California has 16 spots where books have been "released into the wild."
The site is great. There is a link to the most traveled books, one of which is the EuroBookCrossers' Diary #1. What a cool idea is that. It's like some sort of wired exquisite corpse journal.