I thought I’d finish up the five days of St. Patrick’s Day madness with the king of Irish beers – Guinness. The beer itself comes in a gleaming black can with the instantly recognizable harp logo on the outside and a clever nitrogen widget hiding within. Many people don’t know it but the fine folks at Guinness actually invented the nitrogen widget. They did this so that the beers they sold in stores would match the quality of their beers when served in the pub. A brilliant concept – beautifully executed. When pouring a pint of Guinness Draught, the widget instantly turns the beer into an inviting tan froth. As…