I used to have a Philips 100Hz CRT TV, which used digital processing to 'double' the frame rate. One nice feature was it had a freeze-frame feature, back when

I used to have a Philips 100Hz CRT TV, which used digital processing to 'double' the frame rate. One nice feature was it had a freeze-frame feature, back when such things were pretty rare. So the party trick was to leave it on showing frozen black and white 'snow', and when someone mentioned it just say 'oh, it's stopped again' and bang on top of it with my fist. The snow would then start moving again, in the usual manner. The trick was, of course, furtively pressing the 'unfreeze' button on the remote control in my other hand.