According to a trivia question from a game whose name escapes me, humans take an average of seven minutes to fall asleep after they've hit the pillow. That means if you have a nightlight, it's not really being used for about 95% of the night, earning you a bad mark on your efforts to go green. You could always use a timed nightlight, but the Hourglass Nightlight can take your nocturnal eco-friendliness to the max.

Designed by Sun-Young Lee, the Hourglass Nightlight lights up as sand streams from top to bottom, using the potential energy of the falling grains to power it — no batteries, no plugs. Once the last grain falls, it goes dark. But if, say, nature calls in the middle of the night, just flip the Hourglass to light your way. It's just a concept right now (and a slightly dubious one at that, since grains of sand falling a few inches probably wouldn't add up to much wattage), but a cool idea for a gadget. We wouldn't mind seeing this guy grace the shelves of Brookstone. — Peter Pachal

Via Yanko Design