Kennedy Space Center was really really neat. I loved seeing how the shuttles were made, the Saturn 5, and the way NASA looked when they sent someone to the moon.
I also really loved the Star Trek Exhibition. They had abunch of the costumes from Star Trek (like Troi's dresses, Data's uniform, Kirk's uniform, etc) They had phasers & communicators, and the bridge from The Original Series! So, we all got to sit in Captain Kirk's Chair.
The Shuttle Launch simulator was pretty neat (but really bumpy) however I will NEVER be getting on a G-force simulator ever again. Never ever.