At MIC we do something called a 'Drum Circle'. In this we sit around in a circle and drum out rhythms to the rest of the circle. Each child has slightly different percussion instruments, which might even be clapping. A facilitator in the middle helps to synchronise the drum beats.
Typically larger drum sounds tend to lay a steady and slower beat, and the lighter or higher sounding percussion instruments tend to go faster. Think of a bass drum in a band, compared to a tambourine. Now if the group is playing well, then actually the children have to learn how to keep time in fractions or multiples of their neighbouring drummers. So the deep drums lay down 1 beat per measure; the middle drums might go twice as fast; and the smallest drums might lay twice that speed again - ie 4 beats per measure. The children are concentrating on laying down an synchronised rhythmical performance; but we think they also happen to be learning about numeracy albeit in a slightly unusual way.