I haven't seen a game do it yet, but would like to see how others celebrate different holidays, not from the U.S.
It's kind of like when you bring out new trees and you have to wonder if that tree really exists or not.
Having a lot of variety makes people think and have the urge to research, which in turn becomes a learning tool. I'm sure the developers would find it fun and challenging as well, maybe get out of a rut?
I love this game
