So it's March 14 again, and that means it's time to celebrate everyone's favorite irrational real number, Pi. Pi Day (and its slightly nerdier twin, Pi Approximation Day) are unofficial holidays marking the calendar's trip past 3.14. (Pi Approximation Day is held on various dates related to Pi, like the 314th day of the year).

On Pi Day, enthusiasts celebrate Pi by eating pie (or pizza), watching the movie Pi, playing ping-pong, or our favorite: memorizing just enough digits of Pi to outdo their calculator. (In my case, that would be 3.14159265358, which I memorized in ninth grade instead of paying attention in math class.)

If you're in San Francisco, check out Pi Day festivities at the Exploratorium. There's a shrine involved, and a rapping Einstein puppet.

...Which leads us to this last tidbit: Pi Day is also Albert Einstein's birthday, which makes it extra-special for _flossers.