Great idea! A light powered by gravity. Lift the weight up and your light works for 1/2hr. Nothing else needed. Hopefully they'll get the funding to bring this forward to the whole world! Can't find where you can buy these yet, but they will be $10 staring out, and will be $5 and work twice as long if they get funding.



If that embed doesn't work, here's the link:

http://www.aei-ideas.org/2012/12/markets-in-everything-the-amazing-gravity-li...