The Age of Aquarius may have come and gone by the time Hair was released, but the “mystic crystal revelation” remained. Milos Forman's adaptation of the 1968 stage musical underscores the joy and jubilation of a youth ethos gone pandemic. An introverted Okie, Claude (timidly nuanced by John Savage), wanders into New York's Central Park and is adopted by a tribe of multicolored hippies, led by George Berger (Treat Williams), a leather-fringe dweller. Claude has been drafted and wants to spend a few days learning about love, liberation, and lysergic acid. Using a racially mixed cast, lascivious lyrics, and cultural triumphalism, this wiggy work helped define the notion of the “rock musical.” Choreographed with controlled chaos by Twyla Tharp and chock full of chemically uplifting songs, many of which made the pop charts, like “Aquarius,” “Good Morning Starshine,” and “Easy to Be Hard,” Hair is a full-tressed tribute to the spiritual transcendence of late-sixties counterculture. “Long as God can grow it. My hair.”