Three IBM engineers and three Microsoft engineers
Three IBM engineers and three Microsoft engineers are travelling by train to a conference. At the station, the three Microsoft guys each buy tickets and watch as the three IBM engineers buy only a single ticket between them. "How are three people going to travel on only one ticket?" asks a Microsoft employee. "Watch... and learn." answers an IBM engineer.
They all board the train. The Microsoft guys take their respective seats but all three IBM engineers cram into a restroom and close the door behind them. Shortly after the train has departed, the conductor comes around collecting tickets. He knocks on the restroom door and says, "Ticket, please." The door opens just a crack and a single arm emerges with a ticket in hand. The conductor takes it and moves on.
The Microsoft guys see this and agree it was quite a clever idea. So after the conference, the Microsoft guys decide to copy the IBM engineers on the return trip and save some money. When they get to the station, they buy just one single ticket between them for the return trip. To their astonishment, the IBM engineers don't buy a ticket at all! "How are you going to travel without a ticket?" says one perplexed Microsoft employee. "Watch... and learn." answers an IBM engineer.
When they board the train the three Microsoft guys cram themselves into a restroom and the three IBM Engineers cram into another one nearby. The train departs. Shortly afterward, one of the IBM engineers leaves the restroom and walks over to the restroom where the Microsoft guys are hiding.
He knocks on the door and says, "Ticket, please."