March 14 is the official day for
Pi Day derived from the common three-digit approximation for the number
Pi, 3.14. It is usually celebrated at 1:59 pm (3.14
159). Parties have been held by
mathematics departments of various schools around the world. This is not to be confused with
Pi Approximation Day[?] on
July 22.
See also: Mole Day, Yellow Pig Day, Programmer's day