Hoyl cr4p man, asking what to do is SoCal is like asking where to go in New York City.
But to help you, there a some awesome clubs up in LA on Sunset. Most are pretty decent, not sure what you like. Hope you're over 21 btw.
Long Beach promenade isn't so bad, some good bars. If you're a youngin, hit Disneyland/Knotts. The beach isn't super in that area but head down to South country and you're quality.
Go see Catalina Island if you're from somewhere inland where the ocean is new and exciting. If not, don't bother. ITs pretty but not exceptional. If you're bringing a signifiacnt other, its romantic though.
Good luck.