This bulb has built-in solar panels so it can be used in places off the grid.

Made by Nokero the rain-proof light bulb is about the size of a standard incandescent bulb and contains a replaceable, rechargeable battery that can be charged during the day to provide light at night. Nokero says the N100 is designed for the 1.6 billion people who live without electricity and rely instead upon lanterns that burn fossil fuels. Full story here.