Way back we had terminals with an internal PSU that supplied -12V GND +5V +12V.
Took a 6 inch 12V fan and superglued a threaded nut to one blade so it was way off balance, cable-tied it loosely to the underside of the operators desk and wired it across the -12V and +12V.
When the terminal was powered on the off balance fan hammered against the bottom of the desk and it almost started walking across the floor.
Biting the hand that feeds IT
