The date today resembles 3.14159, the common approximation of the mathematical constant Pi, or π. This concurrence has given rise to an annual celebration from 1:59 pm - also the time of publication of this post (CET).

What is Pi? 

Understanding Pi is essential if you want to make calculations for circles, cylinders, spheres, and anything circular, even an ellipse. Pi is the ratio of the circumference of a circle to its diameter. It doesn't matter how big or small the circle is - the ratio stays the same. Properties like this that stay the same when you change other attributes are called constants.

-The Nobel Prize