Pete

Well, most scholars agree that "Pete" is "St. Peter." But it's a little-known fact that the "sake" in the phrase was originally pronounced "sa-ki" which is a type of Japanese liquor that, eh, St. Peter was well known for enjoying, and because in those days it was brough overland from Japan via the trade routes to Rome, it was quite expensive. So, people would say, "That's for Pete's sake" when they had a lot of money that they would give to the church. Eh, of course, this was in the days before he was Pope.