Have a few partners together and do any of the basic drills (push up, sit up, leg raise, squat) very slowly (60-120 count) as you move start saying the numbers one at a time and every seven divider you say something else instead of it (it can be boom, go and so on) As long as everyone is aware and relaxed you continue but if one misses a divider such as saying you start from the start again. Have fun and keep all your faculties aware when you work.