In Los Primos (Cousins), an unlimited number of performers participate in the evolution of a perennially unfinished musical composition. It is at once an instrument, a recording, a score, and an experiment in the musical intelligence of crowds. This Web-based piece works on three levels: as a score that generates sound derived from the interaction of players; as a repository of performances; and as sound material for incorporation into subsequent performances, which then become archived and utilizable again, ad infinitum.