Saw these for 1,900 nickels on Fancy. Very cold war.
After seeing these nickel cufflinks I googled around for other functional cufflinks and found the following (a lot of them can be found on a UK based watch part company):
Movable time and date
Working sand timer
Called the Square ball game. The balls move but I'm not sure this makes it a game.
This one however, is a real puzzle.
Levels in cool blue.