Pavegen has build tiles that generate energy when people walk over them.

The latest version of the tiles also come in a triangular shape, with a generator in each corner, which maximizes energy output no matter where you step.

In Lagos, Nigeria, the tiles were installed under a soccer field, and players lit up the entire field during a match:

Source (Elyse Wanshel, “Tiles That Generate Energy When People Walk Over Them Are Totally Lit”, Huffpost, 23.06.2016)