The counterculture themes from the 1960s Broadway smash hit Hair revolutionized theater in a way that only psychedelic hippies could. With its vast assortment of underground subjects—drugs, anti-war sentiment, civil rights, and sexual freedom (the company takes it all off for one scene)—the rock musical carried dance, music, and stage production to a whole new level. Inspired by its songs, the cast members of the Public Theater’s upcoming outdoor production of Hair present Be-In, a concert about peace, love, and understanding that benefits Broadway Cares/Equity Fights AIDS. So feel free to join in this communal celebration and sing your freedom-loving heart out. We just hope they won’t be administering an AIDS test.

Mon., July 7, 9:30 p.m.; Mon., Aug. 11, 9:30 p.m., 2008