Everyone into a circle for a silly warm-up to get the blood flowing.
Players randomly and unexpectedly jump up in to the air. At some time in the air they clap their hands. Since other players are also jumping and clapping at the same time the name popcorn seems appropriate. If two players clap their hands at the same time they are out of the circle for a few seconds only to join in later. The exercise is continued until hands become sore or someone sprains an ankle.
Players that are out of the circle stay out but continue to jump and clap their hands, but do not worry about simultaneous claps. Eventually there is an outer and inner circle, and eventually there are only a few people in the inner circle with many people in the outer circle. The warm-up ends when there is only one circle, or the elimination process can start again.