Wired : We already know there’s pent-up demand for holidays, typified by the number of official – and unofficial – holidays out there. Take Super Bowl Sunday, which is more widely celebrated than most official holidays. Take Black Friday, our post-holiday celebration of another contact sport, of sorts: shopping. Take April Fool’s Day, a celebration of pranks and human gullibility. And then there’s Pi Day (March 14, or 3.14 – get it?), a celebration of circumferences, math, and store-bought cherry pie.