Who doesn't love an aquarium?!
A great local museum that has many different cultural exhibits!
American Ballet Theatre's Sylvia will be on stage 4/9-4/12.
If you don't mind a bit of a drive into LA, the Villa is a great museum to see ancient Greek and Roman art and culture. It's free admission but does need a reservation time.
General Admission is Free. Their collection changes often so it's always worth a repeat visit.