The Arthur Guinness Day Toast is on the Fourth Thursday in September at 17:59 ... 

  THE ARTHUR GUINNESS DAY TOAST               Diageo came up with Arthur’s Day four years ago to celebrate the beer’s 250th birthday.       The time,   17:59,   refers to the year the Guinness brewery was founded.         It has since morphed into a nationwide festival every September.       The London-based company is staging 500 concerts as part of the event,   with bands including Manic Street Preachers   and the Script turning up at bars.     Arthur’s Day is a “unique music festival,”   according to Peter O’Brien,   a spokesman for Diageo.