[Ani Niow] built this steam powered vibrator. It has a milled stainless steel shell with a brass motor structure. The motor is a Tesla turbine made from a stack of Dremel diamond cutoff wheels. This drives an off-center weight to create the vibration. She tested it using a pressure cooker as the steam source. It worked, but became so hot it had to be held using welding gloves. It works just as well with compressed air though. You can see the device at the Femina Potens Art Gallery in San Francisco or later this month at Maker Faire.
[via Laughing Squid]
UPDATE: [Ani] responds in the comments.