We recently visited the Arizona-Sonora Desert Museum (September 2005) and had a great time. It was quite a drive from where we live, but it was worth the drive. If you're traveling between now and the 30th of September, be forewarned that you must take alternative routes due to Gates Pass closing.
The Arizona-Sonora Desert Museum was a combination of a zoo and a desert garden. As we walked along the trails, we were greeted by beautiful panoramic views and bugs/animals. Our pictures consisted of cacti to beavers. We were hoping to see rattlesnakes and coyotes, but didn't have any luck in finding them.
Along the trail is a building where you can view works of art. In this same building, you
can also make crafts (drawings, headbands, origami, etc) for the little ones. It is also air conditioned so it's a nice place to take a break.
Water fountains are located all over the museum. The great thing about it is it's surprisingly cold! Just in case you're not aware, this museum is outdoors! Also, be prepared for the road that leads you to the museum... it's like riding a roller coaster!
It was a great learning experience and a great exercise! It was also inexpensive to visit... just go early; we missed out on the gift shop.