Point to the person in your group most likely to do each thing. They must own it.
1.Stop to read every historical plaque
2.Ask a local for a recommendation and actually go there
3.Take the most photos of the city skyline
4.Get on the wrong bus or metro and end up somewhere interesting
5.Find the most unexpected hidden gem restaurant
6.Spend the whole trip in one neighborhood they love
7.Bring home the most unusual souvenir
8.Overspend at the local market
9.Make friends with a stranger in a coffee shop
10.Know more about the city history than the tour guide
11.Try every variation of the local specialty dish
12.Get completely turned around and still look confident
13.Be the last one ready to leave a place
14.Find the best deal on anything in the city
15.Look most like a local
16.Discover the best street food stand
17.Stay up the latest to experience the city at night
18.Find the museum exhibit that nobody else was interested in
19.Take the group somewhere they did not plan to go
20.Already be researching the next city before this trip ends