The Irish car bomb (a shot of Irish whiskey and Irish cream dropped into a pint of Guinness) is a standard St. Patrick's Day cocktail, though its origins aren't commonly known.
Come St. Patrick's Day everyone's Irish, and they all want to express their newfound ethnicity with goofy hats or at least some green gear. I found the ten most bizarre St. Patrick's Day crafts on Etsy that you'd only buy after a few pints o' Guinness...
While many people associate St. Patty's with heavy drinking and pub crawls, in Ireland, St. Patrick's Day is a historically solemn and sober holy day for Roman Catholics. Believe it. Until the 1970s, pubs were actually legally required to close up shop for the day.