Today is the day yes March 14th 2008 where many math enthusiasts are celebrating Happy Pi Day, first of all Pi, Greek letter (), is the symbol for the ratio of the circumference of a circle to its diameter. Pi = 3.1415926535.

Since the infinite formula begins with 3.14, Pi Day falls on the 14th day of the third month, hence March 14. The celebration starts officially at 1:59pm, continuing the first six digits of Pi, which are 3.14159.

Source - Official Site