Simple, but even as an adult (well, I'm still a child mentally) I enjoyed going to the local Krispy Kreme and going on the tour. Yes, most Krispy Kremes offer tours so you can see the frying machine up close and witness the making of all that is unhealthy and tasty.
Ask your local airport if they give tours. Tampa International does if you call them ahead of time and its free -- its part of a "seeing your tax dollars at work" program. They take you along the runways, let you watch the planes, operate the firetruck (lots of buttons! woo!) and explain the general workings of the facility, hangers, etc. Another internal tour that I haven't taken, yet, shows the luggage sorting system and security equipment. These tours still happen despite security elevations with the only change being that they don't take you into the tower, anymore.
I can't quite explain the awe felt when we got to be directly under a landing plane.
The "snozzle", which is pushed through the skin of a flaming aircraft to inject water. We were permitted to play with the controls for it.
Buttons!