Math geeks rejoice: It's National Pi Day.

Since it got support from Congress eight years ago, Pi Day has been observed with some degree of fanfare-much of it on social media. Named for π (pi)-the mathematical term for the ratio of the circumference of a circle to its diameter-Pi Day is observed March 14 because the ratio is roughly 3.14159265 when rounded.

Congress served up Pi Day, in part, to encourage schools to promote math, at the urging of groups such as the Association for Competitive Technology, the American Chemical Society and the Biotechnology Industry Organization. Even actress and Ph.D. Danica McKellar (Winnie Cooper from The Wonder Years and a Dancing with the Stars contestant) was a supporter.

On March 12, 2009, the U.S. House of Representatives passed a resolution proclaiming March 14 as Pi Day. Introduced by Democrat Bart Gordon from Tennessee, the resolution: "Supports the designation of a Pi Day and its celebration around the world. Recognizes the continuing importance of National Science Foundation math and science education programs. Encourages schools and educators to observe the day with appropriate activities that teach students about Pi and engage them about the study of mathematics."

For more information, go