People tend to check in during these times:
It's not immediately apparent, but there is additional parking at the rear.
Go on a day where the children are at a low level to enjoy the place to it's fullness.
Visit the amateur radio exhibit. It's open most days, and isn't as much aimed at kids. On some days, they can contact the international space station (although it's a bit random when they can).
Do not eat at their cafe--ridiculously overpriced!
Bring the kids, camera and a homemade lunch !! Great picnic place.. :)
Avoid the cafeteria, it is ridiculously expensive and noisy.
Plan lots of time. Tons for the kids to do
The summer camp programs here are great.
March is Engineering Month. Lots of special activities going on.
A voir!!!!! WOW!!!