A man walks into a bar and sees a sign that says, "Free drinks for a year! Just complete the challenge." Intrigued, he asks the bartender what the challenge is.
The bartender explains, "You have to do three things: first, you have to drink a gallon of whiskey in under 10 minutes. Second, there's a rabid pitbull in the back that has a sore tooth – you have to pull it out with your bare hands. And third, there's a 90 year old woman upstairs who hasn't had sex in 20 years – you have to give her the time of her life."
The man looks at the bartender in disbelief, but decides to give it a shot. He downs the whiskey in record time, stumbles to the back to face the pitbull, and comes out a few minutes later, covered in scratches but holding the tooth triumphantly.
Finally, he goes upstairs to the old woman's room and there's a lot of screaming and moaning coming from behind the closed door. After about an hour, the man emerges, sweating and exhausted.
The bartender asks, "Well, did you complete the challenge?"
The man nods and says, "Yeah, I did. Now where's my free drinks for a year?"
The bartender replies, "Well, first of all, you have to pay for those drinks. And secondly, the challenge was just a joke – but I have to say, you're the first person to ever actually try it!"