Nerds rejoice — it's Pi (π) Day! March 14, long extolled as the day immediately following this author's birthday, is also cherished among mathletes, mathematicians, and followers of the I F'ing Love Science Facebook page alike, due to the coincidental fact that 3.14 is both this particular date written in shorthand and the first three digits of Pi. What makes today's instance of Pi Day amusingly exceptional is the further coincidence that Pi's next two digits match the year — 3.1415. Of course, it doesn't quite stop there. Pi is an irrational number, which means its digits continue on *ad infinitum*. Think of it as a Buzz Lightyear of numbers, though perhaps a little less invested in space lasers and more concerned with the area of a circle.

If you slept through your four years of high school math (it's understandable), here's a brush-up on why Pi is so important. Among the neat facts:

— A circle is always a little more than 3 times its width around. The mathematician Archimedes approximated this ratio to be 22/7.

— In recent years we've been able to calculate Pi to over a trillion digits.

— The first 39 digits past the decimal are all you need to accurately calculate the spherical value of the universe. No big deal, right?

If these facts have gotten you excited, here are some additional reads you may find of interest:

— From *Mental Floss*, a remembrance of the time Indiana's state legislature was nearly duped into changing the value of Pi.

— From Exploratorium.edu, Pi to 1 million digits, just in case you were curious. Fun fact: the millionth digit is "1."

— 5 fun facts about Pi from NPR's Math Guy, Keith Devlin of Stanford University.

— Here's the late Leonard Nimoy as Mr. Spock demanding the final digit of Pi, from an episode of *Star Trek*.

Finally, here's perpetual Debbie Downer Neil deGrasse Tyson reminding us that our current exceptional Pi Day isn't really all that cool, at least not compared to one from 423 years ago:

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```Best Pi-Day Ever: 53 minutes & 58 seconds after 6 o’clock, March 14, the year 1592: 3/14/1592; 6:53:58

— Neil deGrasse Tyson (@neiltyson) March 14, 2015

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