What other hobby...

tk21, you and Douglas_Schroeder ain’t no fun. You both took a light hearted question way too seriously. I loved all of the answers except those from both of you. I fear you are both too contentious and defensive to ever be on my party list. 

Macrame

I got into antique jukeboxes around 1990. Buying, restoring, selling, collecting, etc.  I'd be up untill 3 am working on them.  I had nine at one point, I have three favorites now.  I joined the American Historical Jukebox Society.  Meetings, a newspaper, jukebox shows, jackets, the whole works. I met guys with so many jukeboxes they had no room for furniture. I still love those darn things I just don't put in that much effort these days. It was great fun, no regrets. 

I'm with oldheavymech in that I have a lot of gas still in the tank.  That said...
Downhill skiing.  I enjoy the art of tuning my skis and getting the most out of them.  Quick, sharp, and precise turns that secure the most g-force.

Offshore fishing.  It takes a lot of trial & error, and patience, to get those elusive bluefin tuna.  But when you do, especially the bigger ones at between 60 to 150 lb., what a thrill and what a reward.  All other pelagic species are a great catch too, but those bluefin tuna are the best thrill of them all.

Hand loading ammunition for competition.