From the Examiner "Last night, Saturday October 13, 2012, streets near Hollywood Blvd. and Vine Street were blocked off by police, as the L.A.P.D. attempted to shut down a riot, which began at the premiere of a skateboarding movie called ‘Bake and Destroy’. As theatergoers attending another film with a recent premiere, ‘Argo,’ exited the Arclight Cinema parking garage, they were met with dead-stopped traffic, helicopters overhead, screaming fire trucks, and closed streets.
Earlier that evening, around 7:40 P.M. near Go Burger at Sunset and Ivar, several small groups of skateboarders wearing hoodies, aggressively passed pedestrians on the sidewalk, before speeding into the street, flipping off and shouting at some drivers in cars stopped at the light. At the time, the skateboarders could have simply been heading to the premiere, but by 9:00 P.M. a riot was breaking out. According to the Hollywood Reporter, at about 9:15 P.M. a woman tweeted from the ‘Bake and Destroy’ premiere, “There's a full blown riot with police in riot gear at Hollywood and Ivar.” A tweet just prior to 10:15 P.M. from a Fox 11 helicopter in the area reported, “Hollywood LAPDMetro showed up and everybody ran. They didn't even start pushing them yet.” One message re-tweeted multiple times, “This was us! Haha Skateboarders Riot in Hollywood.” Thrasher Magazine’s website has a link to the trailer for the film, with the tagline, “Skateboarding has a lot characters, but this squad is just beyondo."
Check some video: http://youtu.be/aD7Bs_dNvXg
From reading some of the reports seems like a crowd of 500 skaters was enough to make someone call for back up. Bummer the premier had to be cancelled.