10 Guinness's in 10 Minutes

An American walks into an Irish pub and says, "I'll give anyone $100 if they can drink 10 Guinness's in 10 minutes." Most people just ignore the absurd bet and go back to their conversations. One guy even leaves the bar. A little while later that guy comes back and asks the American, "Is that bet still on?" "Sure." So the bartender lines 10 Guinness's up on the bar the Irishman drinks them all in less than 10 minutes. As the American hands over the money he asks, "Where did you go when you just left?" The Irishman answers, "I went next door to the other pub to see if I could do it."