AquaSD man! Zoo is pretty awesome. Balboa park right next to it is nice too. Old downtown is fun for a couple hours (near airport). Might be a little chilly for the beaches but it's socal, so it might actually be nice right now weather-wise.
Or make a short drive to Dana Point (40 mins?) and take the ferry to Catalina Island. It's a little expensive but a nice, once in a life adventure since you're out there anyways.
The beach was really cold when me and my wife went but nice views. Balboa park we enjoyed and the zoo was really fun. My wife loved the shopping as well. Hollywood was just a little drive away and was fun but got crazy after it dark. Enjoy
