The classic bar joke by which all other bar jokes are measured:

Why the long face?
A horse walks into a bar.  Bartender says, "Why the long face?"

The physicist's elegant version:

A proton walks into a black hole.

Those sons of bitches gave me a chihuahua?

Two guys walking their dogs on a sunny day build up a mighty thirst for a brew.  They pass the local bar but a large sign says "No Dogs Allowed (Except Seeing Eye Dogs)".  One guy says to the other, "I'd love to go in, but we can't go in with the dogs, and we can't leave them outside."  The second one answers, "I have a great idea.  We're both wearing sunglasses, just do what I do."

He walks into the bar with his dog, approaches the bar, and asks the bartender for a Guinness.  The bartender says "I'm sorry guys, you can't bring your dogs in the bar.  Sign posted outside."  The guy answers, "Hey man, we're blind.  These are our seeing eye dogs."

The bartender replies "Seeing eye dog?  Your dog is a chihuahua."  The man quickly replies "Chihuahua? Those sons of bitches gave me a chihuahua?"


We don't serve food here

Hot dog walks into a bar.  Bartender says, "We don't serve food here."


I'm just trying to give up drinking

An Irishman moves to New York, and looks to find a neighborhood watering hole where he can plant his roots.  He finds a great little spot, and goes in for the first few weeks, always ordering three Guinnesses at a time from the bartender.  He drinks them in rotation, a sip from each, until all three are finished, then he leaves.  After a few weeks of this, the bartender approaches him.  "You know, the Guinness would be fresher if I drew them one at a time for you.  You don't have to order them all at once like that, you know."

The Irishman answered, "I know that, but it's a family tradition.  When I left the old country for New York, I left my two brothers and parents behind.  My dad made me promise to order my beers three at a time, and drink them this way to remind me that I should be sharing them with my brothers."

The bartender is so touched that a tear comes to his eye, and he buys him a round on the house.  The Irishman becomes a regular, always ordering his Guinnesses three at a time.  One day he walks into the bar and says "Two Guinnesses, please."

A hush fell over the bar.  After the GUinnesses settle the bartender carefully folded his apron on the bar, and brought the beers over to the Irishman.  "I'm so sorry about your loss", the bartender said.  "What are you talking about?"  said the Irishman.  "Well, it's clear that you must of lost one of your brothers, since you only ordered two beers.  I'm so sorry for your loss."

"Oh, my brothers are both fine", said the Irishman.  The bartender aksed "So why did you only order two beers?" 

The Irishman replied, "I'm just trying to give up drinking." 



C'mon you little bastard, spit it out

A Brit, an Irishman, and a Scot are in an outdoor cafe having a few beers.  Just as the waitress brings their Guinnesses, a fly lands in each of their beers.  The Brit pushes his beer away, "I can't drink this beer, it had a fly in it."  The Scotsman flicks the fly out of his beer, "It's a crime to waste a good Guinness", he said.  The Irishman grabbed the fly by the wings and held him over the beer.  "C'mon you little bastard, spit it out."