When Bud and his friend Bugs reach "Hooverville," the cardboard jungle of homeless people, they are reluctant to approach the people around the campfire. To decide who will have to do it, Bugs takes a penny from his pocket and says "Heads I win, tails you lose."
The coin landed on the tails side, so Bud lost. But look at how the wager is worded--Bud would have lost had the coin come up heads, as well. In fact, the wager is rigged such that there is no way for Bugs to lose. This is a classic "no-win" gag bet that ensures whoever makes the statement will win.