Escape Room: Set the Clock
Using an analog or digital clock, remove the batteries/unplug to stop the clock. Set it on a three digit or four digit code of a combination lock. For example, if the pass code to the lock is 1134, stop the clock's time at 11:34. The players should notice the clock has stopped and figure out that it is a code. If the clock is not on a wall, put a note on it 'do not touch' so they won't move the time on it and lose the code.
Props needed for this scenario:
Clock on the wall / on a desk.
Locked box, suitcase, traincase, etc.