Pi Day, E Day, Phi Day and other math-related holidays

Today, as of the time of the posting of this is March 14, which is Pi Day:

https://en.wikipedia.org/wiki/Pi_Day

Yes, there's a holiday dedicated to the number π (pi), which is 3.1415926....

Similarly there is an E day, or Euler's Number Day, February 7, which celebrates the number e, or Euler's constant, which is 2.7182818.... :

https://www.timeanddate.com/holidays/fun/e-day#:~:text=Euler's%20number%20is%20commonly%20celebrated%20on%20February%207.&text=People%20living%20in%20countries%20that,digits%20of%20e%20(2.71).

There's even a Phi Day, or Golden Ratio Day which is June 16:

https://www.mentalfloss.com/article/546530/happy-phi-day-last-day-match-golden-ratio-century#:~:text=According%20to%20Bloomberg%2C%20June%201,digits%20of%20the%20golden%20ratio.
https://www.mentalfloss.com/article/546530/happy-phi-day-last-day-match-golden-ratio-century#:~:text=According%20to%20Bloomberg%2C%20June%201,digits%20of%20the%20golden%20ratio.

Phi is 0.618033988749894....

Does anyone here care about all this? If so, Happy Pi Day 2021!

What math-related holidays do you like? Feel free to discuss about them here.