He asks the bartender "Hey, what's with the jar?"

The bartender replies "Well, we have a running challenge here in the bar. It has three parts. If you look at the end there, you'll see Big Jim. Big Jim is the baddest motherfucker in town. You have to knock Big Jim out."

The guy looks down to see a 6'4 300lb guy and says "Well, I don't think I can do that. What's the other two parts?"

"After that, you have to go outside. Around back is where we keep Big Jim's dog. He's the baddest junkyard dog you've ever seen. You have to go get a tooth out of his mouth. And then, when you're done with that you have to go upstairs. There you'll find Big Jim's mom. She's 70 years old and never had an orgasm in her life. You've gotta go up there and fuck her to completion."

The man says "Wow, I can see why the jar is so full."

After a few hours of drinking the man get sloppy drunk and says "Fuck it," slaps down a $100 and jumps up on the bar and runs down and kicks Big Jim square in the jaw knocking him out cold. The bartender is stunned, as this is the furthest anyone has made it. The man runs outside to the cheers of the patrons and everyone hears snarling and growling and grows silent. Moments later they hear the dog whimper and then yelp, then nothing.

Moments later the man drunkenly stumbles back in and says "Alright, now where's the old lady with the tooth?"