Here's a twist on one mentioned already.

You know, St. Patrick didn't really drive the snakes out of Ireland.

What he did was, he opened a pub for tourists in Dublin, and offered platters of fried snake, free with a pint.

Business was great till the supply ran out, but by then he was making out okay driving customers back to the docks for the ferry ride home. You know? I suppose you could say maybe he did after all.