The wife turned me on to this place when we were searching for something local to do over the weekend and I was greatly impressed! We ended up spending the entire day at Springs Preserve because it is such a large place and there are quite a few exhibits to see, trails to walk/ride, and plenty of places to practice photography.
Since we're locals, we only paid $20 to get in ($10/ea.) and, at the end of the day, they allowed us to turn that $20 into a $45, two-person annual pass!
I took over 500 pictures that day and only spent time in about 60% of Springs Preserve.
Check out my photos here: http://www.panoramio.com/user/8631485/tags/Springs%20Preserve. That will give you an idea of what you'll see and what you can do.
The Divine Cafe is a great place to take a break, relax, and eat some great food. They also serve wine to go along with your pizza or other food offerings.
We don't have kids, but there were quite a few playing around in the kids playground and we were able to see the butterfly exhibit which was awesome!