Geeks, nerds and math whizzes celebrate National Pi Day on 3/14. Since today is Sunday 3/13, we say it is a great day to enjoy a piece of pie. Whether you make your own, order one for dessert or drive through a fast food place, one piece of pie can make today special. And you can tell people you celebrated ‘Pie Day’ day early – they will be duly impressed. But we will know the truth.