This one’s been making the blog rounds, but it really fits us. Nintendo makes one, but this instructables tells you how to make your own for a DS lite. It uses a PIC 12F675 to read the input line and activate a vibration motor from an old nokia cell phone.

Oh, speaking of instructables, I forgot to mention that they finally picked a winner for their laser etching machine. Of course, if you lack the budget, you can make your own for $60.