Cambrian House, famous for 'crowdsourced software,' is raising money for Youth For Technology in an interesting way. They have taken a MacBook and are getting is signed by all sorts of tech luminaries and then auctioning it off to the highest bidder. Straightforward and simple, just the way I like it. You can even track where the MacBook is, or read their blog.
The first signer is none other than Guy Kawasaki, who will now send it off to someone else to get signed and so on.