March 14, written 3/14 in the USA date format, is the official day for Pi Day derived from the common three-digit approximation for the number π: 3.14. It is usually celebrated at 1:59 PM (in recognition of the six-digit approximation: 3.14159). Some, using a twenty-four-hour clock rather than a twelve hour clock, say that 1:59 PM is actually 13:59 and celebrate it at 1:59 AM instead. Parties have been held by mathematics departments of various schools around the world.
Tuesday, March 15, 2005
Some random trivia: Yesterday was Pi Day. Quoting from the wikipedia article,