Takes from the ArXiv: Hydrogen π

This paper is cool (though surely someone must have done this before).

It rederives Wallis' formula for π by looking at the spectrum of the quantum-mechanical description of the hydrogen atom. (It does this with a variational computation of the spectrum.)

A Shotgun Approach to Calculating π

Here is a literal(!) shotgun approach for calculating an approximate value for π. I approve! (I think...)

Now let me quote from the arXiv paper (which is called "A Ballistic Monte Carlo Approximation of π"): "We compute a Monte Carlo approximation of {\pi} using importance sampling with shots coming out of a Mossberg 500 pump-action shotgun as the proposal distribution."

Pi = 3.2?

Well, apparently the lovely state of Indiana once attempted to legislate the value of Pi to be 3.2. That was a rather irrational thing for the Indiana state legislature to attempt.

On a similar note, you should read the article Alabama Pi in this book.

(Tip of the cap to Jed Yang.)