4/11 is a Monday. =( What are your plans for the weekend prior? Are you staying somewhere near Anaheim?
Anyway, I think you'll have a lot of fun at San Diego Zoo! Some things to look forward to:

Gorons.

Polar bears sleeping in kiddie pools.

Lions that want to eat you (and have a spray range of 7-10 ft.).

Tigers that play like house cats.

A lynx that sleeps in a hammock.

Pandas.

Panda bags (I still use mine to this day!)

Panda cups (free refills all day if you buy one of these)
Tip: Don't make barley tea in your giant panda cup. It's been a year and a half, but I still can't get the smell of barley tea out of my cup!