Somehow I came across this website and poked around looking at the different lists for Atlanta and Savannah. It is packed with information and would be useful if you are trying to find something fun to do for the day or plan a vacation or weekend trip.
This is a Southern Living article from 2006. It might give you some ideas of fun stuff to do without leaving the Southeast.
The Gwinnett Environmental and Heritage Center has not been around too many years. It is supposed to be neat and they even host birthday parties.
When you need to get out of the house, why not try one of the almost 40 parks scattered around the county. This tells more and links to info about each park. And, yes, there are more on the way.