I ran across this video of a guy starting up a Rolls Royce passenger jet engine in his backyard:
https://youtu.be/TXqW9TXCExI
What a dedicated nutter, he even had an APU for start power, a big steel cradle to hold the engine, and a roll away hanger. Engine instrument panels, etc. I kept asking why?
I am guessing he is a Brit, sheep in the paddock next door running away, and deciduous trees; and they are renown eccentrics.
What are the strangest hobbies you have heard about, not astronomy ok.