Get ready to party with your scientific calculator: Saturday is Pi Day.
Pi is the symbol for the ratio of the circumference of a circle to its diameter. It's commonly represented as 3.14, but has been calculated to over 1 trillion digits past the decimal.
Saturday's date, 3-14, coincides with the first three digits of pi.
Math enthusiasts will mark the day with pi eCards, pi T-shirts and -- believe it or not -- pi raps.