We found out that there was a brand new 747 parked at LAX, one of the first off the line. It wasn't in passenger service yet, but it was open for anyone to take a self guided tour!
So we ran down there and wandered around the 747, visited the cockpit and everywhere and went up and down the staircase a few times.
I'd been on airplanes before, but never one with a spiral staircase. It was awesome!