Cry much? Then maybe your tears could be powering this lantern next time. In all seriousness, all you need to power this lamp is a salt shaker and some water. Green House Co Ltd has developed an LED right that runs on salt water. Granted your tears are probably not enough.

Take this out to your next camping trip and mix up a saline solution of salt and water to keep it glowing for up to eight hours at a time. It's definitely much cheaper than batteries. So put this on our wish list! The salty mixture serves as an electrolyte between a set of magnesium and carbon rods inside the lantern, a negative and positive rod.

But it won't last forever. The magnesium rod is only good for about 120 hours of electricity production, but replacements will be sold separately when the lantern goes on sale sometime this month. [Green House via Tech-On!]