I like endeavors where I can use my hands, and I generally enjoy digging down and learning everything I can about whatever my current interest happens to be. When I started biking, my biggest free-time activity was learning how to bikes are built, and eventually building one. Now I'm a biker and I bike nearly daily but I don't read book after webpage after book about it anymore, and other things have taken the limelight. So... my hobby might be 'learning new things.'
The one thing I've always got my eyes trained to is cooking. A few years ago I learned everything about being vegan, then I learned everything about Carribbean cooking, then Ethiopian, then Indian... I started up baking a year and a half ago, and now I'm on to classic American food... but I'm always building, so everything I've learned continues to be used.
I'm super interested in reading about economics. I think that's the only pursuit that takes a lot
of my time that isn't translated into something tangible in my life.