Los Angeles Times, 2005:

Gangsters, nightclubs and rock ‘n’ roll make up much of the Sunset Strip’s colorful history — along with a little-remembered tussle in 1966 that became known as “the Sunset Strip riots.”

The melee erupted as young rock fans were protesting efforts to enforce a 10 p.m. curfew and to close nightclubs that catered to them — including Pandora’s Box, at the corner of Sunset and Crescent Heights boulevards.

The confrontation with police also inspired musician Stephen Stills to write “For What It’s Worth,” released two months later by Stills and the band he was in, Buffalo Springfield.

“Riot is a ridiculous name,” he said in an interview. “It was a funeral for Pandora’s Box. But it looked like a revolution.”

The club, painted purple and gold, was perched on a triangular traffic island in the middle of the Strip. It drew a crowd of mostly clean-cut teenagers and twentysomethings wearing pullover sweaters and miniskirts.

Ensuing traffic jams annoyed residents and business owners, who pressured the city and county to get rid of the kids, the clubs and the congestion.

It’s unclear from Times files whether Pandora’s Box or other clubs had been closed by the time the protests began. But young rock fans interpreted efforts to enforce curfew and loitering laws as an infringement on their civil rights.

On Nov. 12, 1966, fliers were distributed along the Strip inviting people to demonstrate. And hours before the protest, “One of L.A’s rock ‘n’ roll radio stations made an announcement that there would be a rally at Pandora’s Box and cautioned people to tread carefully,” wrote Domenic Priore, author of the 2007 book “Riot on Sunset Strip: Rock ‘n’ Roll’s Last Stand in Hollywood.”

Stephen Stills wrote a song about it:

Read Mike Davis’ seminal recounting of what led to the riots here: PDF.