Vi Hart, who knows more about math than I ever will, made a video and two pies especially for Pi Day, which she says we should call Half-Tau Day. She lost me when she said a pie is really 2pi, because I never took that class. I will take a slice of cherry, if you don't mind. Link -via The Daily What
@kakungulu: Personally I find the "US" choice to be the most elegant solution. Maybe not the most practical but, if you want to talk practicality I think a more specifying order would be better stating the year first, then the month, then the date. except the year doesn't change quick enough for the average person to forget, so It's best to keep it last or just leave it off entirely. e.g. 3-14-2011, 3-14.
As to your comment about it being only the US... in china I believe the standard way of writing is “?????” which translates out to ??=3rd month ???=14th day. Exactly like the US.
If you change pi even by a factor of just 2 you will have to change the Euler's relation and that will throw all all this fancy calculus that is the basis of modern science.
Next thing you know my airplane falls out of the sky because someone forgot to divide by two somewhere.