Obsessed with free love and political activism, San Francisco in the 1960s was a haven for artists and activists, and those energetic souls, in attempts to spread their passion, stamped the city with posters. Last year, the Denver Art Museum came into possession of 875 of these vintage works, and to give design buffs, music lovers, and art historians a chance to revisit the past, the museum holds its first-ever exhibit of psychedelic rock posters. Pieces by artists such as Wes Wilson, who designed posters for the Avalon Ballroom and Fillmore Auditorium, and Victor Moscoso, a Yale University-trained color theorist, hang as they once did in the streets of the City by the Bay. Through July 19. Tue-Thu 10 a.m.-5 p.m.; Fri 10 a.m.-10 p.m.; Sat 10 a.m.-5 p.m.; Sun noon-5 p.m. Denver Art Museum, 100 W. 14th Ave. Pkwy., 720-865-5000 $15