No, your eyes aren't deceiving you! National Pi Day really is a whole 24 hours dedicated to celebrating Pi, the ratio of a circle's circumference to its diameter!
But then, if you're a maths expert you'll already know that. It's been a while since I was in school studying maths and I'm a little rusty!
So do you know why Pi is so interesting? Well it's a transcendental number meaning it's infinite - no mathematical operation can be the equal to its approximate 3.14 value.
This is why it has fascinated and confused mathematicians for centuries and possibly many more to come!
It even made the news after a Japanese psychiatric counsellor recited pi to 83,431 decimal places from memory - setting an unofficial world record!
Larry Shaw recognised the significance of all this and created Pi Day on 14 March - the 14th day of the 3rd month (3.14, geddit?!). It's even been passed as a non-binding resolution by the House of Representatives!
Past pi day activities included walking round a circular section of the Exploratorium art and science museum in San Francisco - before marching back and eating fruit pies!
If you fancy getting involved check out the pi rap online or visit the official National Pi Day website.
Or bake a cake - delicious and its not like you'll ever run out of numbers to fill the round shape!