A stranger crash lands on an island full of polar bears and smoke monsters, and is being escorted around a village that he has just become part of. He is shown a well when his guide says "On any day except Friday, you can shout any question down that well and you'll be told the answer."
Impressed, the man shouts down, "Why not on Friday bro?" A voice from deep within the well replies, "Because on Friday, we grind."