Sorry, but the "true" math geeks are waiting for March 14, 2015 at 9:26 and 53 seconds AM to celebrate. Until then, we'll keep our differential equations and T-distributions to ourselves.

Invented in Borat's movie. It is said, when something great happens.

March 14th. A "holiday" celebrated by math geeks everywhere. Pi is approximately 3.14, and March the 14th is 3/14.

One of several days, notably march 14th, 3/14, and the 22nd of July, representing a common fractional approximation 22/7. It's somewhat of a pointless holiday, but it's always fun to annoy the hell out of people by being able to recite digits of pi from memory.

a day celebrated by math geeks across the world on march 14th

March 14th. A "holiday" celebrated by math geeks everywhere in USA and anywhere else the date is formatted MM/DD/YY. Pi is approximately 3.14, and March the 14th is 3/14 in America.

(March 14th)
A holiday celebrated by math teachers and geeks everywhere.
March 14th was the chosen day because pi = 3.14.
Since the next three numbers in the sequence are 159, at 1:59, everyone celebrating must say, "Happy Pi Day!"
And please, don't ask how I know.