For upcoming π day (Tuesday 14th March), I’ve started putting together a notebook of interesting snippets of Julia code that somehow involve π:
https://github.com/simonbyrne/Pi.jl
I would love to have more contributions: please add to the notebook and open a pull request. If I can collect a reasonable number in the next few days, then I will put together a blog post for julialang.org to appear on the day.
If you’re looking for some ideas, here is a thread from a couple of years ago.