Since Saturday is Pi Day of the Century, I am starting the celebrations early by wearing my t-shirt today. I got this as a gift from my better-half. This fits my geeky and nerdy side to the T. π Day was started by Larry Shaw of the San Francisco Exploratorium in 1988. This is Pi Day of the Century because of the sequential time that will occur on 3/14/15 at 9:26:53 following the sequence of pi.
From Wikipedia, a few Pi facts:
The number π is a mathematical constant, the ratio of a circle‘s circumference to its diameter, commonly approximated as 3.14159. It has been represented by the Greek letter “π” since the mid-18th century, though it is also sometimes spelled out as “pi” (/paɪ/).
Being an irrational number, π cannot be expressed exactly as a common fraction, although fractions such as 22/7 and other rational numbers are commonly used to approximate π. Consequently its decimal representation never ends and never settles into a permanent repeating pattern. The digits appear to be randomly distributed; however, to date, no proof of this has been discovered. Also, π is a transcendental number – a number that is not the root of any non-zero polynomial having rational coefficients. This transcendence of π implies that it is impossible to solve the ancient challenge of squaring the circle with a compass and straightedge.
In August 2009, a Japanese Supercomputer called the T2K Open Supercomputer was claimed to have more than doubled the previous record by calculating π to 2.6 trillion digits in approximately 73 hours and 36 minutes.
In December 2009, Fabrice Bellard used a home computer to compute 2.7 trillion decimal digits of π. Calculations were performed in base 2 (binary), then the result was converted to base 10 (decimal). The calculation, conversion, and verification steps took a total of 131 days.
In August 2010, Shigeru Kondo used Alexander Yee’s y-cruncher to calculate 5 trillion digits of π. This was the world record for any type of calculation, but significantly it was performed on a home computer built by Kondo.The calculation was done between 4 May and 3 August, with the primary and secondary verifications taking 64 and 66 hours respectively. In October 2011, they broke their own record by computing ten trillion (1013) and fifty digits using the same method but with better hardware. 
In December 2013 they broke their own record again when they computed 12.1 trillion digits of π.