As for the nudity, I remember it (not doing it, mind you!) from college days. And the novelty song by Ray Stevens. :-D
There's a running club in my area that holds an annual race at a nudist colony, which is again being held ("wear a mask! No one will know who you are") this year despite other races being canceled. The organizer (Ron Horn) even got a callout in the
New York Times running newsletter
(June 20 edition).
No, I don't plan to run there this year, either. ;-)