Pi Day happens once a year and we really should celebrate it in style.
Although it happens every year I'm always surprised to find that Pi day has crept up on me yet again. Today, assuming you are reading this on the 14th of March, is Pi day. Of course the date has been chosen because it is 3/14 i.e. third month 14th day and these are the first three digits of Pi.
Now you might think that this is something only worth celebrating if you are a mathematician but Pi has an importance for programmers, computer scientists and just about anyone doing anything practical.
Pi Pie, created at Delft University of Technology, applied physics, seismics and acoustics
At its simplest Pi is simply the ratio of the diameter of a circle to its circumference, but Pi holds many other secrets. The most mind numbing is that it is not only an irrational but a transcendental number. What this means is that while other numbers can be defined as the solution of a reasonable looking polynomial equation  e.g. x^2=2 defines the square root of two as its solution  no such polynomial exists for Pi. (To be precise the polynomial has to have rational coefficients  there are obvious equations that specify Pi that have irrational coefficients like x=Pi.)
What all this means is that Pi is a strange sort of number. It has enough regularity to be computable  i.e. there are lots of formulae that can be used to calculate it to any particular digit  but is is also irregular enough to be beyond the range of a simple polynomial.
There are so many things that are interesting about Pi that it could occupy a lifetime's research and for many mathematicians it has and does.
How to celebrate Pi day?
Many people use the tenuous and arbitrary connection between Pi and pie and simply bake and eat a celebratory pie on Pi day. Lucky for us it wasn't called poison or something less edible!
If you have any other good ideas email us and meanwhile we have some related articles you might be interested in:
Noncomputable numbers
Computability
Yahoo! Gets to the 2 Quadrillionth bit of Pi  it's zero
More Information
http://www.piday.org/
http://en.wikipedia.org/wiki/Pi_day
