We went there Friday while Dean was at zoo camp (so fun for the kids, BTW - unless they get bit by a dog!) and had plans to go again on Labor Day. We had free entry coupons expiring that day AND it was the last day of the monorail ever so our friends really wanted to go before it was too late. It does take some creativity to keep all the kids entertained for a full day, as our friends were wanting to visit the whole zoo, and we usually last a couple hours and then head home.
I REALLY liked this printable Scavenger Hunt I found on Teaching's a Hoot's blog. It has questions like "What animal has feathers?" and "Find an animal with claws." Visit her blog for the 2 page printable.