My son's Head Start class last year went on a field trip to the Huntington Museum of Art. They do have some interesting pictures where people took 2 pictures & put them together to make one. Like if you look real close at a picture of water, you may see hands in it or something...odd, but interesting.
The rain forest I have to say was the best part, not only for myself but for the kids as well. They had fish in ponds, various plants like Venus Fly traps, flowers from different parts of the world.trees, bushes that were trimmed to look like animals.
Not sure if they charged or not, as it was a field trip. This is a place that I would go to maybe once a year or so. Not something you would want to go to all the time.
They do have craft activities for children during the summer time on weekends. A nice something to do with your child(s) if you live around the area.