Psych-Out (1968)

Deaf runaway Susan Strasberg arrives in San Francisco searching for her long-lost brother Bruce Dern and is taken in by a trio of hippie musicians, including Jack Nicholson. They help her search for her brother while also teaching her how to be less square. I have no idea how accurate it actually is to the era, but it is filled with free love, mind-altering drugs, and lots of groovy tunes.