Oops ... forgot Pie day
Pi Day and Pi Approximation Day are two holidays held to celebrate the mathematical constant π (pi). Pi Day is observed on March 14, 3.14 being the first three digits of pi. It can also be celebrated on March 4 (when 14% of the month of March has elapsed). Pi Approximation Day is observed on July 22, due to π being roughly equal to 22/7. Pi Minute is also sometimes celebrated on March 14 at 1:59 p.m. If π is truncated to seven decimal places, it becomes 3.1415926, making March 14 at 1:59:26 p.m., Pi Second (or sometimes March 14, 1592 at 6:53:58 a.m.).