When is a Bet a Sure Thing?
From the Guys and Dolls movie,
Sky Masterson: One of these days in your travels, a guy is going to show you a brand-new deck of cards on which the seal is not yet broken. Then this guy is going to offer to bet you that he can make the jack of spades jump out of this brand-new deck of cards and squirt cider in your ear. But, son, do not accept this bet, because as sure as you stand there, you're going to wind up with an ear full of cider.
One modern update:
Note how the bet was cleverly coerced.
Our modern day Guy didn't ask, who wants to bet? Nobody wants an earful of cider.
Rather he said, "How much do you have?" Answer, "A tenner". Bet's on, whether the holder of the tenner wanted to wager that much or not!

