Hiking - got into it because I was in the scouts as a kid. I found it boring and exhausting and onerous as a kid, until I went on my first backpacking trip. For me at least, feeling committed to a multiday journey from A to B kind of removed the distractions and what-ifs, and allowed me to really sink into the experience of being outside like nothing else had. Going backpacking is my number one trick for becoming a happier human - exercise, in nature, good circadian rhythm, disconnected from the internet.

Climbing. Got into it because I was looking for friends to go backpacking with in college, and they were into climbing, too. While backpacking can feel very relaxing, climbing feels very in-the-moment. A difficult route will challenge you in any number of ways - physically, as your lungs burn and your forearms start giving out; mentally, as you try to figure out a sequence of moves to make it up while managing the risk of falling; and emotionally, as you work through your fear of falling off and balance your mind between focusing on the task at hand and being open to all possibilities. You develop great friendships, since you tend to get comfortable with someone you are trusting your life with pretty quick. There is always something new to learn, as there are many disciplines from gym to outdoor, rock to ice to aid to mountain, and boulder to sport to trad. And it takes you to amazing places - sure, you can plan a trip to Chamonix or Thailand to go skiing or hang out on the beach. But when you make plans with a climbing partner, you actually buy the plane tickets. You fly in and immediately depart from the normal tourist circuit, getting a much better feel for life for the people in the areas you are travelling in. Then you show up in your destination, and you don't just look at the beautiful scenary - you are part of it. You don't just look at the mountain - you are perched on a tiny ledge on the side of it, watching the birds hover next to you while your partner cruxes out on the next pitch above.

Canyoneering. Similar to climbing, but easier to do with lots of friends of various skill levels. While climbing is often a fairly serious endeavor with defined goals, a canyon just has a single general goal that the whole group works on together: get out of the canyon. Thus, canyons tend to be a lot more fun and social, and often involve silly shenanigans like throwing a bag over a wall to have a rope to climb, or standing on a friend's shoulders while another lets you grab their foot to lower yourself over an edge.

DIY. I dunno, I just intrinsically like the idea of being able to build and fix all my own shit. Sometimes this feels less like a hobby and more like a job, but it is hard to beat the satisfaction of finishing a project that then makes your life better every time you use it.