I grew up in the Washington D.C. area and my favorite museum was always the Air and Space Museum on the Mall. Of course, the reason for this was that for years, I thought we shared the same first name, mine is Aaron and thought the museum was the "Aaron Space Museum."
When we took my older DS, now 12, to Orlando for the first time (he was 7) he thought everything that went on in the rides was REAL. He was worried that they would not be able to get us back from the past on Dinosaur (it was still Countdown to Extinction then) and needed reassurance that Disney would make us big again after they shrunk the audience.
The ride he had the hardest time with was Terminator 3D at Universal Studios, however. When Sarah Conner came on screen at the end of the preshow and frantically warned us we had 3 minutes to get out of the building, poor Jordan was panic-stricken. We barely convinced him that it was just a ride, and he refused to wear the 3D glasses in the theater. He liked this ride much better when he rode it at age 10!