What if there were a palm-size charger that gathered power from the wind? A company called Humdinger says its Microbelt small-scale wind charger actually works, and it's 10 times more effective at generating wind energy than other units its size.
Where is the turbine, you ask? There isn't one — it uses "aeroelastic flutter and vibration of a membrane" for its wind power, operating sort of like that blade of grass you put between your thumbs to honk out some choice noises.
The amount of energy created by this diminutive device is minuscule — but it's efficient, outputting 2 milliwatts when the wind is blowing at 5.5 meters per second. That's enough power to run building monitoring and transit monitoring sensors; with one of these, there'd be no need to ever change batteries. Put a few dozen of these on an electric car, and you'll have something pretty close to a perpetual-motion machine.