Micro generator turns environmental vibes into electricity
This is so cool. 
Micro-generator feeds on good vibrations - tech - 04 July 2007 - New Scientist Tech
A sugar-cube-sized electric generator that feeds on environmental vibrations has been developed. It could power swarms of wireless sensors or even medical implants, researchers claim. The new micro-generator harvests power electromagnetically, exploiting the wobbling of several magnets attached to a millimetre-sized cantilever. It measures just 7.0 millimetres by 7.0 mm by 8.5 mm, and the team behind it say it is the most efficient micro-generator yet developed. The generator converts 30% of environmental kinetic energy into electrical power, and could keep all sorts of low-power devices running without batteries – particularly when alternatives like solar power are not an option.