This is a little early for Pi Day (3/14), but I'll post it anyway so everyone can start getting ready:
On Pi Day, you eat pie. It's as simple as that. I routinely celebrate the day with my roommates. One year, we even made it a point to each eat a radian's worth of pie. Marvelous stuff. I'll be sure to recognize the holiday this year. Don't you be caught unaware. Purchase your pie today.