Defense Tech's Bryant Jordan was at the Disneyland of military gadgetry—the Modern Day Marine event at Quantico—and came across this power-generating backpack, which has stepped from prototype to reality. It can generate 40 watts just by walking.
It works great, apparently. The backpack itself is mounted on rails, so it moves up and down when its wearer moves. The movement generates enough electricity to power your gadgets, and the design actually relieves stress from the user. [Gizmodo via Lightning Packs via Defense Tech]