"The Orb" - a mobile headset that doubles as a ring. It can be used 30 feet away from your phone, vibrates on your finger if you get a call and has a voice-to-text device, so you can read messages on your ring.
Come on now,I bet you could find all sorts of uses for a small device that vibrates on command. I guarantee that if they made one that could be adjusted to the proper size I'd buy one tomorrow!