As if cell phones don't already encourage enough annoying, disruptive public noise, researchers at Sungkyunkwan University in Seoul have developed a phone battery that you charge by yelling at it.
The battery has zinc oxide wires running between two electrodes; sound vibrates the wires, and that creates electricity. Right now, it only works with sounds over 100 decibels, which is unfeasibly loud — think motorcycle, chainsaw, or train. (It would be good for motorcycling rail-riding lumberjacks, though.) But in theory, batteries like this could charge off the sound of your voice, or — ideally — the obnoxious cell phone chatter of the people around you.
The best part about this: It harnesses the human instict to shout at things that aren't working. Phone runs out of juice, you yell "goddamit, phone, no, what the hell?!?," phone has juice again. Go science!