The Sonic Bomb Alarm Clock from ThinkGeek sports “an adjustable volume alarm with a maximum loudness of 113 decibels (just for reference, a jackhammer is about 100 decibels!) — and the bed shaker does just that.” Video after the break. Click here for one more picture.
Slip it under your mattress and your ears will bleed and your bed will shake, and there is no way you will oversleep. Or, you could turn the sound alarm off and tape the bed shaker to your office chair