It is also Albert Einstein's birthday and, sadly, this year's edition marks the passing of Stephen Hawking, about which I'll have more to say later. But for now, let's celebrate Pi!
Calculate Pi yourself!
NASA's Pi in the Sky Challenge
A few videos:
(That one's titled "Pi Day" but the video has nothing to do with Pi so far as I can see, but it's a cool video anyway, so there it is.)
Happy Pi Day, everyone!