Playing golf with his buddies, my grandfather had to make a slick 25-foot putt.  As he lined it up, he announced, "I have a dollar bill that says I can make this putt.  Does anyone want to bet?"  His three friends eagerly agreed to the wager.  My grandfather missed the putt by ten feet, and his friends gathered around to collect their money.

Granddad pulled out a dollar bill on which he had written, "I can make this putt." 

His pals are still trying to collect on the bet and grandpa is too.