Bobby McFerrin plays an audience.
Many people can play instruments. The violin, the drunks, the piano, or the tuba are all conventional instruments. Turntables, beat boxing, or an MPC are less conventional, but I haven’t seen anyone use an entire audience as a musical instrument. Bobby McFerrin demonstrates how the Pentatonic Scale is universal, and can be used to make music without people realizing the complex nature of their actions. Its pretty sick.