Adafruit Industries Adafruit Industries Vibrating Mini Motor Disc
*BZZZZZZZZZZ* Feel that? That's your little buzzing motor, and for any haptic feedback project you'll want to pick up a few of them. These vibe motors are tiny discs, completely sealed up so they're easy to use and embed. Two wires are used to control/power the vibe. Simply provide power from a battery or microcontroller pin (red is positive, blue is negative) and it will buzz away. Works from 2V up to 5V, higher voltages result in more current draw but also a stronger vibration.
Adafruit Industries Vibrating Mini Motor Disc