There are several recent trip reports posted here. You might do a quick search and come up with several ideas.

I'm not much for zoos (I'd rather see animals in the wild), but we did enjoy the Night Safari. It's very well done and all the animals were very active. Don't miss the giant fruit bat enclosure.

The nature preserve also has some good hiking. Generally you will spot monkeys, birds, some funny little squirrels and, if you have sharp eyes, maybe some lizards and snakes hiding out. As we learned though, don't mess with any of the brightly colored ones.