hobby? what hobby?
As a kid, building scale model kits was a passion. Mostly planes & ships, including subs. The more detailed and complex, the better. Then came rocketry - to the degree that I was rolling my own body tubes rather than use what Estes had in their catalog.
Later it was cars - rebuilding engines, which was around the same time I was building full-size submarines (see how things can snowball?).
Now, aside from reloading, fixing things around the house keeps me pretty busy. I've not touched my golf clubs in years other than to move them out of the way. Raising kids isn't exactly a hobby, but some of the activities, like camping, chaperoning field trips, eight years as a Cub Scout leader might qualify!
As far as related hobbies, IDPA competition and Appleseed events are the closest, as they both have ties to firearms and marksmanship.