Sparkfun Electronics SparkFun Surface Transducer Kit

The SparkFun Surface Transducer Kit is essentially just a speaker except instead of a cone, the coil is attached to a pad that conducts the vibration into whatever you press it against. Hook it up to the included MP3 player and press it against the nearest table, wall, or cardboard box. You can even put it against your head and play music directly into your skull (the ultimate surround sound).