Today (3/14) is observed by math geeks everywhere as Pi Day. Pi (π) is the ratio of the circumference of a circle to its diameter - 3.14159265359.
You can celebrate by finding the circumference of a circle, using math formulas learned in grade school, or reward yourself with pi's delicious phonetic twin: pie. And in case you were wondering how big the pie business is in the U.S., we put together the above infographic. Have a happy Pi Day!