I think we can get away with Mahjong Solitaire as an in-joke. It's not like we're popular and it'll invade the fandom.

Which, by the way, is what happened with Donuts - I was there when it was born. A girl in my flist started it as a joke ("if Harry/Hermione can have a stupid name like Pumpkin Pie, I can call them Donuts!" or something along those lines). And then it was all over the fandom and she was all "uh, I was joking".