Ever wonder who picked up (besides the cleaning crew of course) that just read paperback that you left in the seat pocket of your last flight? Go to Bookcrossing‘s website to register the book(s) you want to set free. Voila, you can now leave a book anywhere in the world and track what happens to it. Kind of a “Where’s Waldo” type of thing. Also, if you just happen to “catch” a left book somewhere…you can track back and find where it came from. Fun for kids and adults.