Happy Pi day! Google celebrates in style. A mathematician gives a rare Pi interview. Many of us eat Pi(e) for dinner (we had dutch apple pie – not as cute at the picture, I’m afraid).

But some purists are claiming that Real Pi Day is actually April 17, when the Earth is 1/? from the winter solstice:

March 14 is the vulgar Pi Day. Sure, calling 3/14 “Pi Day” may seem cute, and it makes for good media coverage, but the commemoration of a transcendental constant should not be tied to the grubby political vagaries that resulted in the Gregorian calendar’s accidents of number.

The 3/14 date may be a “vulgar,” but Pi is great enough that we can celebrate it more than once a year. And don’t forget, Pi Approximation Day is coming up on 22-7. More Pi(e) for everyone!