My parents had the "Armageddon Clock" on the wall of the living room.
It was a wall clock where you could manually move the longer minute hand and the hour hand would just follow.
My father cut the power cord off. I'm not sure at exactly what year they started using it, but it was likely the late 1060's. Each 5 minute increment was a month, so 60 minutes was a year. My father moved it once a month.
For example, on October 1969, there would be 6 years left until October 1975, so the clock would be at 6PM. The next month he would move it to 6:05 PM, the next month to 6:10PM, etc. When it reached October 1970, then it was 7PM. When the clock finally reached mid-night (12PM), that would be October 1975.
Needless to say, it reached 1975 and nothing happened. He later threw the clock away and bought one that worked.
Rub a Dub