Initially commemorating its 250th anniversary in 2009, Ireland’s Guinness brewery has made the “holiday” a tradition. This year, Emeli Sandé, The Script and Janelle Monáe are performing at Irish pubs in honor of the Emerald Isle’s go-to brew. Can’t make it to the real thing? Settle for a free pint at Mandalay’s authentic Irish pub (to the first 100 guests at 5:30 p.m.) or score a free Arthur’s Day Guinness glass by ordering a pint of the creamy stout (to the first 50 Victorian Bar guests at 8 p.m.). September 26, 5:30 p.m., free entry.