Nasruddin Hodja was strolling to market one day when he saw a strange, dark shape appear, blocking his path. "I am Death," it said, "I have come for you."
"Death?" said Nasruddin. "But I'm not even particularly old! And I have so much to do. Are you sure you aren't mistaking me for someone else?"
"I only kill people who are not yet ready to die," said Death.
"I think you're wrong," replied the Hoja. "Let's make a bet."
"A bet? Perhaps. But what shall the stakes be?"
"My life against a hundred pieces of silver."
"Done," said Death, a bag of silver instantly appearing in his hand. "What a stupid bet you made. After all, what's to stop me from just killing you now, and thus winning automatically?"
"Because I knew you were going to kill me," said Nasruddin, "that's why I made the bet."
"Hmmm . . ." mused Death. "I see. But . . . but, didn't you also know, then, that I would not be able to kill you, because of the terms of our agreement?"
"Not at all," said Nasruddin, and continued down the road, clutching the bag of money :)