Rather than harnessing the power of wind to be annoying, like wind chimes, the Firewinder takes that kinetic energy and turns it int something actually useful. Lighting.
The $US60 wind-powered outdoor light gets you 14 LEDs and a spiralling effect when it spins. Thinkgeek says that low-velocity breezes of 4 mph is enough to get you "cool light effects", but I"m guessing that if you want something to light your BBQ at night, you're going to have to pray for stronger gusts.
As a decoration, this seems pretty great, and it also tells you how windy it is outside at a glance. As an outdoor light, it seems not all that practical, since the windier it is, the less you probably want to be outside.