Climbing perhaps

Start learning a new language. Babel is a good learning tool. I Learned to speak some German a few years ago. Did it in my spare time. I didn't let anyone know I was doing it and then one day just started speaking German.

Blew the minds of the wife and kids! I didn't continue and didn't have a real application for it so I have already forgotten most of it.

Brazilian Jiu-Jitsu? If you find a school that's got some good technical hobbyists and not meat head competitors. It's an amazingly fun art. I'm 4.5 years into the journey @ 42 years old now.

Another vote for photography. It's turned out to be quite fun to shoot performers including dance, plays, comedy, and more. As photographer you get great access and meet many people. Seeing them happy when you got a great shot during their performance makes it completely worth it.

Some performers requested promo and marketing portraits, and working with non-models to get the right look is a soft skill in addition to the technical side of photography. It's fun, though, as the end result is you're making people happy with your work.