One of the formative events that got me interested in space was visiting KSC during the U.S. Bicentennial celebrations in 1976. We were staying in Orlando, where my father's company was holding a convention, and I tagged along when one of his coworkers' families went on a day trip to the space center around July 1-2.

The things I remember most clearly were the visitor center, where we listened to Kennedy's Rice University speech on telephone handsets (what passed for a "multimedia presentation" back in the day) and saw exhibits on the space monkeys inside, and looked at rocket engines (specifically an F-1) on display outside. Then we traveled to the VAB, where we saw the big exhibition domes outside. I remember only bits and pieces of those displays, and I don't recall seeing the Saturn V or the MLP/LUT, but I remember the VAB very well. We actually got to go into the VAB, and I distinctly remember being impressed when it dawned on me that this enormous hole in the wall we'd just walked through was essentially a gigantic garage door. Yeah, that makes a heck of an impression on a seven-year-old.

Looking around, I found a few pictures of the exhibition:

• Exhibit domes under construction near the VAB.
  
• The completed exhibition area, seen from the VAB roof. Note the Saturn V in the distance, which is getting prepped for a new paint job. Same scene from the opposite angle, with the Saturn V freshly painted and what appears to be one of the MLPs being converted for Shuttle visible to the left of the VAB.

• A trio of astronauts at the opening of the "3rd Century America" exhibition...I wonder if the two on the right knew then that they'd be the next Americans in space.

• Administrator Fletcher visits during NASA Day (7/22/76)
  
• While I couldn't find any more pictures of what was inside the domes, at least one of them appears to have been used at least through 1990 at the KSC press site (later replaced by the NASA News Center building).
  
• The exhibition site a year later, with the domes dismantled and the OPFs constructed.
  
• In 1998, the last identifiable trace of the exhibition was removed, when the Bicentennial logo on the VAB was replaced with the NASA meatball. The giant flag on the VAB is the last actual trace, since it was also originally added to the building as part of the 3rd Century exhibition.

Looks like you can still get your own souvenir mug here, and an exhibit program here, but otherwise there doesn't seem to be much information about the event online.

As for the Bicentennial July 4th itself, about the only thing I remember was our 1974 Suburban getting sideswiped by a drunk driver on the way to the beach to watch fireworks. My father ended up spending part of the evening in the hospital emergency room, getting pieces of shattered mirror glass tweezed from his arm. It was certainly a memorable family vacation that year.