DESCRIPTION:
http://www.evanmchapman.com

"Clapping Music is a minimalist piece written by Steve Reich in 1972. It is written for two performers and is performed entirely by clapping.

A development of the phasing technique from Reich's earlier works such as Piano Phase, it was written when Reich wanted to (in his own words) "create a piece of music that needed no instruments beyond the human body". However, he quickly found that the mechanism of phasing slowly in and out of tempo with each other was inappropriate for the simple clapping involved in producing the actual sounds that made the music.

Instead of phasing, one performer claps a basic rhythm, a variation of the fundamental African bell pattern in 12/8 time, for the entirety of the piece. The other claps the same pattern, but after every 8 or 12 bars s/he shifts by one eighth note to the left. The two performers continue this until the second performer has shifted 12 eighth notes and is hence playing the pattern in unison with the first performer again (as at the beginning), some 144 bars later. The variation of the African bell pattern is minimal; it contains just one additional beat. However, this minimal addition results in a much more interesting piece from the point of view of the variation of syncopation as the piece progresses."

-Wikipedia

...and I just decided to learn it by myself. :P