The day that comes once per year, or once ever depending on definition (by the single Pi Day ever definition, we're about five-hundred or so years too late).
I remember my first true Pi Day celebration at Cascadia. We were having the Physics 123 open house and presentations of our projects. I had built a ballista for that project, which shot paintballs (outside, of course). In the spirit of the day, I had also brought four pies to my display: two key lime meringue and one lemon meringue. The celebration was something else. I really do miss Cascadia.
For this year's celebration, I plan to bring four pies home for my family.
I had already posted this yesterday, but I thought it would be worth it to post it here, too.