Pi approximation day, as opposed to pi day on March 14th (hint: write date in US format, omitting leading zeros)
No idea what we're supposed to do to celebrate either day!
Surely it is total Pi day on 22 July? That might sound a bit irrational but it seems to go on forever.
You should produce a dish of filled pastry, and share it with your circle. It is a good way to meet new people from your area, and to develop a 360 arc of friends.