Tomorrow is March 14.  It is also known as Pi Day.  Pi Day is one of those obscure holidays such as International Talk Like a Pirate Day and Mole Day (my personal favorite).  Pi Day is celebrated by math geeks on March 14 (3.14 get it?) at 1:59 (3.14159.....).

Pi is the ratio of the circumference of a circle divided by its diameter.  It is used extensively in geometry and is represented by the Greek letter pi.  

Pi is interesting because it is an irrational number. This means that it cannot be expressed as a fraction of two integers.  Sometimes pi is expressed as the improper fraction 22/7.  This is not technically correct because 22/7 is a fraction of two integers. Pi goes on forever without the numbers ever repeating or stopping.  So far, over 1 trillion decimal places have been calculated with no end in sight. 

March 14 also happens to be Albert Einstein's birthday--one of the coolest geeks ever. 

To learn more go to http://www.piday.org/ and http://www.wikihow.com/Celebrate-Pi-Day