"Double trouble!" joke

It was a fine summer evening at the local pub in Dublin. The bar was about half full. In one corner two fellows sat drinking pints. One fellow asks the other "Now where are ya from, me lad?"
The second fellow replies "County Cork."
The first fellow is amazed "Why that's were I hail from too! What may be your family name, then?"
The second chap says "It be none other than O'Brien"
"Why that is my clan, too. What a small world. And to what school did you go?"
"I went to St. Brigits."
"My God, So did I!!" exclaimed the first fellow loudly.
"So then, in what fine year did you graduate?"
"1954" "Incredible, so did I!..."
The local bobby (are they called that in Ireland?) stopped in around then to say hello to the bartender. "Every thing OK, Michael?"
"Yes," the bartender replied, "things are pretty normal - the O'Brien wins are drunk again!"