This is a radio that generates its own power, just by cranking it up. It's called The Freeplay radio. It takes about sixty turns to give it a full charge. And you really are just winding up a spring. As the spring unwinds it runs a small generator providing about 3 volts to the device. The radio board is compatable for AM, FM and even short wave.
Features vary by model, but some models even have a solar panel as an alternate energy source. Their Devo Model is even DAB compatible. It's battery, when fully charged provides 25 hours playtime when fully charged. All in all, a fairly green product. ...Though some users complain about the gear noises.
Pulse Planet wrote them up, it's well worth the read: www.pulseplanet.com
CAVEAT EMPTOR: Pulse of the Planet is presented by DuPont! DuPont, the friendly neighbors that brought you such wonder products as Teflon, Nylon, and VX-nerve poison.