look up the Nokia patent on recharging batteries by simply walking with the phone in your pocket, or any movement. Piezoelectric or some damn thing... IMHO it will revolutionise phones.
It's one huge patent to have, rightful for the best phones I ever owned. Too bad they don't have a stronger presence in the US... they are the biggest cell phone maker in the world.
Seiko has been doing it for 20 years and more if you count their mechanical recharging (spring winding) mechanisms:
http://en.wikipedia.org/wiki/Automatic_quartzI had their mechanical watch I really really loved, and really wanted their "kinetic" series when it came out just because of the cool piezo recharging mechanism (the watches were not that pretty, but hey I am a geek). Alas, was too expensive for me. Their "kinetic" mechanism was since used for many other applications such as recharging sensors that are attached to animals in biological studies - let the animal recharge its own tracking device...