How about a lamp that provides you with free and environmentally friendly energy.. forever! All you have to do is water it. Literally.
Soil Lamp is an invention of the Dutch designer Marieke Stapsand it consists of an LED bulb planted in.. mud. The mud is enclosed in cells which contain zinc and copper that conduct electricity generated by the metabolism of biological life.
According to the designer this technique offers a wealth of possibilities, because the more cells there are, the more electricity they generate. The only thing that the lamp needs is some watering every now and then.