A company called M2E power is working on a way to charge your gadgets on-the-go with energy generated from your movements:
According to eco-blog SmartPlanet a company called M2E power, created last year to investigate the possibilities of charging your devices on-the-go with waste energy from your movements, has succeeded in building prototype mobile chargers based around their technologies.
The design is pretty simple: a lithium-ion battery does the juice storing, and the energy is generated when a magnet moves through a series of coils as the device gets jostled about. Put it in your backpack and go about your daily business, and you'll have a nice emergency charger ready when you need it. If you sap it and need more, you'll also be able to steal your company's electricity thanks to the ability to connect it up to the mains for rapid charging.