St. Patrick's Day parades & pub - hopping (2012 analysis)

from Writer's Almanac (Garrison Keillor, American Public Media):

 It was the Irish in America and Canada that turned the saint's day into the full-blown party that it's become. The first St. Patrick's Day parades were held in America during the 18th century, as a show of loyalty to the mother country and a way to call attention to the plight of working-class Irish immigrants. Boston organized the first parade in 1737, and New York's first was in 1762. During the Revolutionary War, General Washington issued a proclamation in 1780 that gave Irish troops the day off for the holiday.
Parades remain a large part of the day's celebrations, and New York City's is the largest in the world, with the 69th Infantry Regiment leading 150,000 marchers up Fifth Avenue. The first St. Patrick's Day parade in Dublin was held in 1995 to boost tourism. Since then, the parade has grown into a five-day festival and attracts millions of people every year. Consumption of Guinness stout more than doubles on March 17; around 13 million pints will be imbibed worldwide today.
American Public Media, St. Paul, Minnesota