Not sure when you are traveling, but the Dodgers are in town for a 4 game series starting on the 5th. Again, this is in walking distance from the Hilton. You can't get much more romantic than a baseball game on a cool spring evening.
agreed with peter. don't take this zoo for granted. it craps on our LA zoo, no joke. don't sleep on this if you haven't been. pay for the sky ride/bus tour, it's worth it -- see animals while you hop from one side of the park to the next.