This one is for all the mathematicians in the crowd. Pi day, celebrated on 3/14 in honor of the first three numbers of Pi, is a day to celebrate the world's strangest mathematical constant. Rattle off as many numbers of Pi that you can, wear Pi-themed T-shirts or accessories. Doesn't matter. Just get some Pi!
Fun fact: Pi Day is actually a holiday that comes twice a year! The second Pi Day, known as Pi Celebration Day, is held on the 314th day of the year. So, if you miss it the first go around, there's another chance come November every year!