By far the most amusing yet depressing thing that happened on my trip to Denver with my 6yo was the following from the first night in our hotel:
Me: Go wash your hands.
Saoirse: <goes into bathroom> There's no soap.
M: <goes into bathroom> They use bars of soap here. <unwraps soap>
S: What's a bar of soap?
M: This.
S: <examines bar critically> How do you use it?
M: You get it wet and rub it between your hands, then wash normally.
S: <gingerly tries> Ooooh that's so weird.