Put this in your "Cool Gadgets" notebook. I know you all keep one. Clay Moulton, a student from Virginia Tech, has invented a gravity lamp, as in a lamp powered by gravity. You can read the full article here. The lamp is powered by a slowly falling weight which spins a rotor to light an LED, and as a result, a weight must be lifted to the top of the lamp every four hours. The lamp puts out 600-800 lumens (enough to light the den), and the machinery of the lamp is estimated to last upwards of 200 years. Way to go Clay.