If you like going to the gym, you know that it feels great to use some of your body's natural energy and really get your blood pumping. However, don't you know that there are better things to do with that energy beyond sweating all over the Stairmaster?

A gym in Hong Kong has hooked batteries up to their exercise machines, harnessing the power of sweaty people to help keep the lights on. The idea of harnessing the energy of the human body isn't a new one, but more and more places are looking to get in on the body-powered craze. A nightclub in Rotterdam is installing a dancefloor that will convert the stomping feet of dancers into energy as well. The problem is, the energy generated by these devices is less than overwhelming — generally just enough to power a small fraction of the lights used in these locations. Hopefully we'll see more creative and efficient ways of harnessing human energy in the future, as lord knows there's gotta be an upside to all those jumping jacks you've been doing. — Adam Frucci

Via The Wall Street Journal