Energy. Kids seems to have an endless supply of it and adults are looking for it to power their devices for living. Those are not exactly the same types of energy but with an invention called the sOccket, one can be converted to the other. The device is a soccer ball (football) that stores the energy it gets from rolling around while being kicked by kids (or adults) in much the same way a shake-to-charge flashlight works. That energy is stored inside the ball and then can be used to power devices.
The ball is intended for use in lesser developed areas where electricity is usually created from dirty burning and expensive generators (if at all). Kicking the ball around for 15 minutes can generate enough power to run an LED light for up to 3 hours. And it’s free off the grid clean energy! The ball is regulation size but it slightly heavier to account for the electronics inside so it does have a slightly different feel.