July 22 - Pie is good for the mousetrap

 Apparently, the poem about the Pied Piper of Hamelin was said that the piper led out the rats on this day in 1376.

So it's Ratcatcher's Day (the Brothers Grimm said it should have been June 26, 1284, who do you believe?)

To catch a rat you need good bait, and what better than pie?  Well, for a mathematician, the best pie is pi.

Today is pi approximation day.  July 22... 22 / 7 ... and if you divide 22 by 7, you can get an approximation of pi.

March 14 - Smart folks commonly know it as pie

How many can you do?

3.14159265358946267338238... at least that's what I remember, but I always order the put the 4626 and it's not 733 it's 793... anyways, that number is important and if you put the numbers as 3 / 14 that's the Imperial way to say March 14th.

Which is today, so today is known as Pi Day.

Interestingly enough it's also sometimes celebrated on July 22, which is 22/7 ... which is the rough approximation of pi.

Also on this day - the 2nd Monday of March - Canada celebrates Commonwealth Day.

Well, as much as Canadians 'celebrate' anything.

It's also Albert Einstein's birthday (he would have been 143), and also the day that Stephen Hawking passed away in 2018.