Pittsburgh - this town is so family friendly, after 8 years we still haven't done it all.
Kennywood - locally owned great amusment park
Sandcastle Water park
Idlewild/soak zone - little bit of a drive from Pittsburgh but with a amusement park and water park in one, how can you go wrong.
Pittsburgh zoo/PPG aquarium
Ducky tours - tour downtown and local rivers on a bus/ship that looks like a duck.
Dozens of Museums (the Childrens Museum is sooo much fun)
Carnegy Science Center (easily spend a whole day there)
Ride the incline for a spectacular view of downtown pittsburgh (great ice cream store at the Mon incline too)
Always great shows to see in the Theatre district
Laurel Caverns for the explorors
I could go on, but I think thats enough for now.