Gunderstank is an efchan catchphrase brought upon by British !ArmyXvICNw , whereas if you are caught posting it anywhere on /ef/, you get an obligatory joke ban. The origin and the meaning of the term are both irrelevant, because the meme, in comparison with "The Game", is the result of a Streisand Effect. But the nonsense of it all was what made it so amusing.
While "Gunderstank" is nothing but a distortion of logic, the proper execution of the game was to keep it the most subtle and unexpected of posts. (i.e. The first letter of every sentence in a greentext story spelling out the name.) Posting it outright makes the game go stale really easily.
I know nothing about the origin of this game. Someone, help finish this article please.