1.) Singing on the train
2.) As soon as they leave the train, looking for a café. Coffee! Butterbeer!
3.) HUFFLEPUFFS IN AMERICA.
"Yo, dude!"
"I'm in 'murica!"
"Forget about the Washington monument, let's go look at the geese!" (Yes, Washington D.C. has several parks with lots of geese. Very nice geese.)
4.) Hufflepuffs being too shy to speak foreign languages, even if they're good at them, because they're so worried they'll mess it up and offend someone. (*cough cough* French and Japanese. You pronounce something just a leetle but wrong and it means something veerrryyy different)
5.) Field trips to muggle amusement parks for Muggle Studies! The Hufflepuffs try a few roller coasters with the Gryffindors, but also really like the kiddie rides like the log flume, the giant swings, and the bumper cars.
6.) Hufflepuffs at the Ministry of Magic waayyy overdressed in fancy clothes
7.) Hufflepuffs are great finders... how about a corn maze?
8.) Hufflepuffs in Edinburgh! They go with Ravenclaw, because then they don't have to pay for a tour guide!
9.) Hufflepuffs do all the touristy things like riding the London Eye, going to the top of the Eiffel Tower, and riding cable cars.
10.) Hufflepuff is the House with the most muggleborns, so they have to explain everything to the other Houses, especially Slytherin.
"What's that???"
"That's a fire hydrant. There's water in it."
"Well, then why isn't it called a water hydrant?"