There's a potential Ig-Nobel worthy paper on arXiv that was submitted earlier this month: A Ballistic Monte Carlo Approximation of π. The authors use a Mossberg 500 pump-action shotgun and an aluminium foil to calculate π with a Monte Carlo approximation. What is their motivation, you ask? From the introduction:

The ratio between a circle’s circumference and its diameter, named π, is a mathematical constant of crucial importance to science, yet most scientists rely on pre-computed approximations of π for their research. This is problematic, because scientific progress relies on information that will very likely disappear in case of a cataclysmic event, such as azombie apocalypse. In such case, scientific progress might even stop entirely. This motivates the need for a robust, yet easily applicable method to estimate π.

How cool is that! Thanks to Gail Gutowski for the tip.