Who pioneered minimal music in the mid to late 1960s and performed in The Festival Dancing in Your Head? 
The Festival Dancing in Your Head:  Composers performed include Steve Reich, David Lang, Michael Gordon, John Adams, Arvo Pärt, György Ligeti, Martin Bresnick, Brian Ferneyhough, Annie Gosfield, John King, Phil Kline, Evan Ziporyn, Béla Bartók. Steve Reich: Stephen Michael Reich ( or ; born October 3, 1936) is an American composer who, along with La Monte Young, Terry Riley, and Philip Glass, pioneered minimal music in the mid to late 1960s.
Steve Reich