Oh, My mate had one years ago... Sort of shitty plasticy thing you buy in a gift shop.

It's in a glass case 'bout the size of an A4 page - Like a small aquarium? The balls are smaller.

It had a wheel/conveyor gizmo which carries a steel ball up to the top of a ramp system (Every 60 seconds) - dropped it down a series of ramps. You read the "time" by counting the amount of balls in each ramp. At the turn of the hour - all the (minute) balls crash to the bottom of the thing, then the process starts again. Pretty sure it was all done off one motor.

I will post a link if I can find one on the net...