My banana (given the right tools) can compute a good estimate of PI using the Monte Carlo method.
I've written a processing code that let's you see the points beeing added to the plot every radioactive event. Consult the internet if you don't know this method yet. It's probalby one of the most inefficient methods to get a numerical estimation of pi, but it works and it's very intuitive.
The code is available in the github repo: