Today's collaboration with What is it? blog brings us this strange device: what is it for?
Place your guess in the comment section - no prize this week, you're playing for bragging rights and fun only. For more clues, check out What is it? blog. Good luck!
Update 5/30/08 - the answer is: An automatic bookmark, it's clipped onto the back cover of a book with the pin placed between the pages to mark your place, patent number D163572.Congratulations to Jim A. who got it right first!