Time-lapse photo of Tesladownunder's "Car Theft Protection" system:

While potentially deadly recreational use of electricity is more than enough to amuse me, this one is especially entertaining since the car is a rental:
My wooden counterweight is on fire here at the top of the coil. It's quite safe to be in the car although my son was apprehensive. This was a Hyundai Getz hire car* (as I don't own one) and it still works. I did get extra insurance "in case".
The above is just one sample from his website:
tesladownunder.com.
Also,
Exploding Easter Bunny (just chocolate, no real bunnies were harmed),
rail guns,
ferrofluid, and on ...
* Australian to American translator: hire car = rental car