Math-savvy pizza and pie shops around the world will be celebrating this afternoon of 3/14 at 3:14 pm to honor the mathematical constant pi. 

Rounding pi to 3.14 suffices for most rational people, but those of you who are trained matheletes might like to carry this never-ending irrational number out to 100 or a 1000 decimal places.  If so, knock yourself out at this post by math.com.  You might as well quit at this point because the record is now 50 trillion digits, held by cybersecurity analyst Timothy Mullican who used 303 days of computation to complete this calculation, which he detailed here.  

A good way to build up your chops on pi is to memorize a ‘piem’, that is a poem in which the length of each word represents a number, for example, “Now I need a drink, alcoholic of course, after the heavy lectures involving quantum mechanics.”  See a much longer (101 digits!) piem sung by musician Andrew Huang and many other amazing feats related to pi in this article by Andrew Whalen posted today by Newsweek.

Sadly, some mathematicians are reigning in the pi parade by insisting it be doubled to the constant tau.

“To describe 3/4 of a circle in trigonometry, you would say 3/4 tau radians. But in the pi world, that’s 3/2 pi radians. ‘Blegh!’ says Prof. [Bob] Palais [Utah Valley University]. ‘People are so ingrained that they don’t even see how stupid it is.’”

For Math Fans, Nothing Can Spoil Pi Day—Except Maybe Tau Day
Wall Street Journal, 3/14/20

You’d best circle (ha ha-math joke) June 28 to celebrate Tau Day, even though that’s no reason to eat pizza or any other kind of pie.