Pi is a Greek letter that represents one of the most useful ratios in mathematics relating a the diameter of a circle to its circumference. Its value is an irrational number, made up of endless decimal places, but most commonly referred to its first three digits, 3.14. Today, March 14th, has become a popular day of celebration for math nerds and other numberphiles, and we almost wanted to post this article at 3:14 PM but we thought we’d get it out early. Here’s our list of the top 5 ways to celebrate National Pi Day in New York City today (yes, it’s an official day)

1. Visit one of the top 5 places to get pie in NYC

Yesterday we got you in the mood for pie, and what better occasion to check out some of the finest locations to get some than National Pi Day! Did you know that 1 in 5 Americans have eaten an entire pie by themselves?

2. Learn all you’ve ever wanted to know about traffic circles

Plaza de Apollo in Madrid, Spain is a roundabout, here’s why.

The number pi (3.14…) is very interesting, but one must not forget that it all has to do with circles. “Get around” to reading our latest Cities 101, highlighting the distinction between a “traffic circle” and a “roundabout.”

3. Play with the NY Times Pi Machine Gizmo, invented by Adam Bowman

Using this quirky interactive, you can calculate the digits of pi using the collisions between two balls by playing with the ratio of their masses. Sound interesting? Check it out.

4. Pi Day Party at the Museum of Mathematics (MoMath)

Today at 6pm, the Museum of Math (MoMath) is having a Pi Day Party eaturing KenKen® inventor Tetsuya Miyamoto and Presidential Teaching Award recipient Dave Masunaga. You’ll also get a slice of pizza pi(e)! The museum says this “annual event is dedicated to enjoying the beauty of mathematics and fostering creativity in the expression of mathematical ideas.” Register here.

5. Read the Congress legislation designating National Pi-Day in 2009

In 2009, Congress designated March 14th as National Pi Day as a way to support education in math and science in America. Read the full bill here.

6. Albert Einstein’s Birthday & the Manhattan Project

The Woolworth Building had offices for the Manhattan Project

Pi Day is also Albert Einstein’s Birthday. Einstein’s letter to FDR jumpstarted research into nuclear research for military bombs. Using a Carnegie website, you can track the locations of the Manhattan Project in New York City, including at the Woolworth Building.

7. Princeton, NJ is the Pi Capital

Princeton, NJ celebrates Einstein on Pi Day with a series of events  including an Einstein look-a-like contest, pie eating and pie judging contests, Pi recitations, and more. Pi Day in Princeton was spearheaded by the owner of the Princeton Tour Company and actively involves local businesses and organizations.

8. Proclaim your love with a Pi sticker for your computer from Macstix

Let pi light up every time you open your computer with this MacBook sticker! Celebrate nerd pride with this vinyl sticker that is applied easily and removed without residue. If you need a larger sticker selection, and much more, we’ve got you covered on the Untapped Cities Shop at Storenvy.

Get in touch with the author @uptownvoice.