Search the clock
Search the clock is a calm and silent searching game for smaller groups.
To play the game, you need a clock with some ticking noise (or a similar "noise generator").
The referees hide the clock somewhere in the room/building. It should be audible from vicinity (at least, if there is silence in the room). The game can either be played in complete silence; if that is impossible, you need more space or some possibility to hide the clock.
As soon as the game is started, the players may search for the clock. It is important to be silent while searching, as you have to listen for the sound of the clock to find it!