The second place winner in the "Greener Gadgets Competition" is Clay Moulton's LED lamp, which uses a gravity mechanism to generate electricity. To light the lamp, you lift the weight and let it slowly fall.

A Virginia Tech student has created an LED floor lamp that is powered by gravity, using a weight slide similar to the concept of a grandfather clock. The lamp puts out the equivalent of a 40-Watt bulb, and lasts four hours per cycle. The mechanism is expected to last 200 years.

To "turn on" the lamp, the user moves weights from the bottom to the top of the lamp. An hour-glass like mechanism is turned over and the weights are placed in the mass sled near the top of the lamp. The sled begins its gently glide back down and, within a few seconds, the LEDs come on and light the lamp, Moulton said. “It’s more complicated than flipping a switch but can be an acceptable, even enjoyable routine, like winding a beautiful clock or making good coffee,” he said.

Link (Thanks, Tom!)