I've seen energy-harvesting remote light switches for sale — they supposedly get enough energy from the physical act of flipping the toggle to send a few radio packets. I haven't used one in the real world though.

Some of the ones at my company require you to stab them with your fingers for 15 seconds like a maniac before they turn the light on.

That would be cool, but I haven't actually seen it in anything other than an old school calculator so I assume the limitations are pretty significant.