I love free energy,...this wont save the world but it may help
You need a Peltier Tile, LED's, voltage booster, wires, thin aluminum and a tiny vice
Step 1: The Power
Wire the Peltier Tile to the booster, and the booster to the LED's
Peltier tiles will take temperature differences and create electricity.
Step 2: Find a Hot Spot
Once wired together find a hot spot in your house,....I used the hot water pipe in my basement.
Place the hot side of the tile on the hot pipe.
Use the thin aluminum to hold the tile to the pipe, this also acts as a cold side extension, then use the vice to take away slack!
Every time my pipe gets warm the light turns on!