22 July 18

It's exactly Pi Approximation Day! The fraction 22/7 has been used as a handy value for π since Archimedes' time, 300 BCE. And so, 22 July (22/7) is honored as ∏ Approximation Day. As explained in the accompanying video, the fraction's value is off by only 0.04%. My cherry pie tie is approximately 100% appropriate for this occasion.

Watch Pi Approximation Day and an Approximate History of Pi.