Pass the Beat Around the Room
Source: Radford College on youtube
Players stand in a circle. Keeping to a steady 4/4 beat, players take turns saying a single syllable of the phrase "pass the beat around the room" (play progresses clockwise). On the 8th beat, that player is silent but touches both their shoulders to keep their place in the beat.
If a player fails to say the correct word (or touch their shoulders) they are out and sit down, but maintain their position in the circle. The other players need to keep track of the players who are out, and act as though they are still in the circle, and playing their part in the rhythm.
To increase the game's difficulty, start substituting other actions for specific words, e.g. stamp your foot instead of saying "beat".