Pi Day 2011 is here: run around in circles and eat some pie to celebrate

March 14 is also 3/14 if looked at in the mm/dd format, and to mathematicians and tech geeks, that's close enough, just as 3.14 is: it's Pi Day.

Pi is an irrational number, and thus cannot be completely represented. However, 3.14 is frequently used in formulas to represent pi, thus the naming of March 14 as Pi Day. 3.1415926535 is pi to a decent number of digits, but computers have calculated pi to over 1 trillion digits past the decimal. Pi represents the relationship between a circle’s diameter and its circumference.

Pi Day is really a pseudo-holiday. Larry Shaw, who worked as a physicist at the San Francisco Exploratorium, created Pi Day in 1989. That event was held with the staff and public joining in, marching around a circular space in the building, which makes sense considering pi's relationship to circles. The party then moved on to feasting, with participants then eating fruit pies.

The Exploratorium continues to hold Pi Day celebrations, but is generally closed on Mondays, and their calendar indicates today is no different.

On March 12, 2009, the U.S. House of Representatives passed a non-binding resolution (HRES 224), which recognized March 14, 2009, as National Pi Day. Meanwhile, last year, on Pi Day 2010, Google used one of its familiar Google Doodle's to celebrating the faux holiday.

Pi Day 2015 will be an especially significant day for pi, and perhaps pie, enthusiasts. That day, 3/14/15, will represent the first five digits of pi, 3.1415.

Sadly, it doesn't appear restaurants like Baker's Square will be celebrating Pi Day. After all, there was already a National Pie Day (with an e) earlier this year.