WaterLight
From Colombia: a portable device that provides electrical power using only salt water. As explained here:
As well as functioning as a portable lamp – half a litre of salt water placed in the device provides an incredible 45 days of light – WaterLight is also capable of charging small appliances such as a cell phone or a radio via a USB port. Perfectly suited to seawater, the device also responds to fresh water mixed with salt and even – in emergency situations – urine.