This may seem quite a trivial matter, but what do you think of wizards playing I Spy? Do you think it would seem too out of place? I personally feel that if things like Father Christmas are universal that a game like I Spy could be too. Fair enough, wizards and witches don't have as many car journeys to pass the time with games, but I'm sure they get bored at times too!
(and is "journeys" the plural of "journey"? I think it is...)