I'm having p(ad tha)i for lunch. Not sure if I'll get any pie today though...
Here are some tidbits from the Wikipedia page on pi.
- The value of π has been known in some form since antiquity. As early as the 19th century BC, Babylonian mathematicians were using π = 25⁄8, which is within 0.5% of the true value.
- The Indian mathematician and astronomer Aryabhata in the 5th century gave the approximation π = 62832⁄20000 = 3.1416, correct when rounded off to four decimal places. He also acknowledged the fact that this was an approximation, which is quite advanced for the time period.
- The Chinese mathematician and astronomer Zu Chongzhi computed π to be between 3.1415926 and 3.1415927 and gave two approximations of π, 355⁄113 and 22⁄7, in the 5th century.
- Even long before computers have calculated π, memorizing a record number of digits became an obsession for some people. The current world record is 100,000 decimal places, set on October 3, 2006 by Akira Haraguchi.  The previous record (83,431) was set by the same person on July 2, 2005 , and the record previous to that (43,000) was held by Krishan Chahal.
- There are many ways to memorize π, including the use of piems, which are poems that represent π in a way such that the length of each word (in letters) represents a digit. Here is an example of a piem: How I need a drink, alcoholic in nature (or: of course), after the heavy lectures involving quantum mechanics. Notice how the first word has 3 letters, the second word has 1, the third has 4, the fourth has 1, the fifth has 5, and so on. The Cadaeic Cadenza contains the first 3834 digits of π in this manner.
- Swedish jazz musician Karl Sjölin once wrote, recorded and performed a song based on and called Pi. The song followed the decimals of Pi, with every number representing a certain note. For example 1=C, 2=D, 3=E etc. The song was then performed as a jazz song, thus making the harmony more liberal.
- On July 22, Pi Approximation Day is celebrated (22/7 - in European date format - is a popular approximation of π).
- It's also Albert Einstein's birthday!
Happy π Day everyone! Do something to make yourself a well-rounded human being today.