[flir]

There's an urban legend in the UK about a radio station having a dead spot in their signal. They send the boffins out to figure out what's going on, and they eventually track down someone who has filled his attic with coils of baling wire and is running his house lights off the radio station.

(Yes, I know all the practical objections. It's an urban legend. I've seen variations involving BBC radio, TV broadcasts, submarine communications, overhead power lines, the VLF transmitter at Rugby, and a farmer using the energy to milk his cows).

[flir]

Oh - and a story that actually happened, in a similar vein: https://en.wikipedia.org/wiki/The_Thing_(listening_device)

[mrguyorama]

The cool thing about The Thing is that it's not really an energy harvesting device, and has no active components. It is a purely passive modulator of a signal being transferred over the air!