Discovery Place is good for kids, we go quite a bit. You could go to Concord Mills, they have the Nascar Speed Park, and large outlet mall. East of town exit 49. We are there daily to get out of the house, we live 5 min away. There is also the Nature Musuem, they have a butterfly room, this is in town also. My kids like going to see that. Not sure how long you are going to be here, the Musuem of the South is in town also. The Whitewater park is west of Charlotte about 15 min or so, can watch the kayakers going down. There is Imaginon in town also, large children's library and depending on your dates you could catch a show put on by the Children's Theatre. BofA Stadium has tours if you are into football. Sad to say we have lived here 9 years and there isn't too much to go see.
Anyway HTH,