Like specific spots where a group of people chill all day. All I know about is "the cannon"/south side of Palisades Park in Santa Monica, and Safe Place for Youth in Venice. It's kinda lonely and boring seeing the same mofos every day.
People kick it around Hollywood Blvd, Sunset and in the nehiborhoods around Santa Monica (street). I would stay out of the neihborhoods unless you're just passing through because people won't be afraid to tell you to gtfo.
