Specifically, it is form of the game tetris played on a yeti. Yetis are notoriously bad for playing tetris on, unless they have cell phones imbedded in them, in which case they are excellent for it.
"I played yetris."
"Wow, you must be knowledgable and sophisticated!"
"You want to go out tonight? I can't. I feel like staying home and playing yetris."