Slightly related: I am probably not the only person who gets cell-phone
signals leaking in all over the place, right?
* Says beep-be-deep in speakers.
* Moves mouse-pointer around.
* Shakes CRT pictures back and forth.
The nastiest thyristor-dimmers might be gone by now, but modern
cell-phones aren't too much fun either.
But useful for testing quality of cables and shielding perhaps?