March 14th for most people is just another day of the week. For math junkies, however, this is the day to celebrate one of the most popular, loved and fascinating number in mathematics pi. Yes, for those who don't know it, March 14 (or 3.14, obviously) is celebrated yearly as pi day.

Pi represented by Greek letter - is simply a relationship between a circle's circumference and its diameter. Divide the circumference with the diameter and you will get its value. It is a mathematical constant however big or small the circle is. It has many uses in mathematics, physics and engineering.

For centuries, the value of pi have been calculated and used. As early as 19th century BC, Babylonian mathematicians were using the value of pi as 25 divided by 8, which is within 0.5% of the true value. Ancient Egyptians put it as 256 divided by 81 or 3.160. Today, the approximate value of 3.14159 is enough to most people. However, people have obsessed to calculate its value up to as many decimal places that they can. And in the age of supercomputers, the value of pi have been computed up to trillion decimal places.

But that's not the end of the story. There are other interesting and amusing facts about this number:

* The English amateur mathematician William Shanks spent over 20 years calculating to 707 decimal places, which he accomplished in 1873. However, in 1944, D. F. Ferguson found that Shanks had made a mistake in the 528th decimal place, and that all succeeding digits were incorrect. By 1947, Ferguson had recalculated pi to 808 decimal places (with the aid of a mechanical desk calculator).

* The first 31 digits of pi do not contain a zero. The millionth digit is a 1 while the billionth digit is 9. The number of the beast (666) appears in the 2440th place. At position 763 there are six nines in a row. This is known as the Feynman Point.

* William Jones, a self-taught English mathematician born in Wales, is the one who selected the Greek letter for the ratio of a circle's circumference to its diameter in 1706. In ancient Greece this symbol denoted the number 80.

* In 1897 the State House of Representatives of Indiana unanimously passed a bill setting pi equal to 16/(sqrt 3), which approximately equals 9.2376!

* In 2006, Akira Harguchi set the current world record of memorizing the value of pi to 100,000 decimal places. He also set the previous record of 83,431 decimal places on 2005. Before that the record is 43,000 decimal places set by Krishan Chahal. (For a list of people who memorized pi, see this site.)

* The most common way to memorize pi digits to several places is to use piphilology a poem or sentence where each word composed of letters that equal the number of each digit in pi. For example, "How I want a drink, alcoholic of course, after the heavy lectures involving quantum mechanics!" translates to 3.14159265358979.

* Singer Kate Bush's 2005 album "Aerial" contains a song titled "", in which she sings pi to its 137th decimal place; however, for an unknown reason, she omits the 79th to 100th decimal places.

* Swedish jazz musician Karl Sjlin 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.

* The band The Seahorses recorded a song called "Something Tells Me". It ends with the lyrics, "What's the secret of life? It's 3.14159265, yeah yeah!"

* In 1998, a movie entitled "" is released. It is about a paranoid mathematician searching for a key number that will unlock the universal patterns found in nature.

* There is a building in the Googleplex Google's company headquarters in California - numbered 3.14159...

* In Buenos Aires, Argentina, the emergency number for mobile phones at trains and subways is 31416

If you want to see (and attempt to memorize) pi up to 1 million decimal places, go to http://people.bath.ac.uk/slt20/milpi.txt.

There's a lot more amusing facts about pi and there are many websites devoted to it in case you are interested to know more.

So, remember to celebrate pi day on 3.14 every year. Oh, and by the way, it is also Albert Einstein's birthday.