By opening Americans' hearts -- and gullets -- to new styles of beer, Channell says, Guinness helped usher in the microbrewery trend, which continues to spread across the country. Despite a decline in overall U.S. beer sales in 2009, the craft-brewing segment -- as microbrewing is known -- rose 5 percent by volume and 9 percent by revenue in the first half of 2009, according to the craft-brewing trade group Brewers Association. Craft brewers sold an estimated 4.2 million barrels of beer in the first half of 2009, up from 4 million barrels in the first half of 2008, the group says.

Guinness, by contrast, appears short of the luck of the Irish these days. Its sales were flat last year, according to the AFP. What's more, overall drink consumption in Ireland is off 4 percent as the country struggles with the worldwide recession. Still, the Diageo brand hardly seems to be in trouble; consumers in 150 countries put back some 10 million pints of the dark ale every day, AFP says.

Given the global marketing appeal of the brand that features a golden harp, the party will be global too. The festivities are to reach a crescendo on Thursday at 17:59 in Dublin, when crowds will be encouraged to raise their glasses "to Arthur" in Ireland, New York, Lagos, Nigeria, and Kuala Lumpur, Malaysia, the AFP reports.

Consumption of Guinness is associated with more than lightness of spirit. Reports frequently surface about its positive health effects, including its reputed ability to ward off heart clots, according to the BBC.

As for Channell, he's not sure yet how he'll ring in Guinness's birthday, but he's got plenty to be cheery about. Business is up more than 9 percent at his microbrewery, even though Michigan is feeling the effects of the recession more deeply than most. "We think people are going out to breweries and the movie theaters, like they do in all recessions, because they want to get out of the home," he says. "They can't afford a long vacation, so this is a good option."