I'm into 3D modeling. It's challenging and makes you always think ahead of what you are currently doing. It has a lot of similarities to programming actually, except that since it's my hobby I'm not trying to be extremely productive and allow myself to work at a slow pace. It is pretty relaxing. Being somewhat familiar with a 3D workflow will also make you appreciate videogames or the CGI you see in movies even more. It also has tons of applications. As an example, I recently moved into a new place but I wasn't sure all my furniture would fit into my room, so I made a rough 3D model of the room and of my stuff and quicky tried different configurations to see which one would work the best.

I've also picked up photography. I don't like sports but I don't mind walking, so it's a great way to actually go outside instead of sitting at my desk all day. On the downside it is pretty addictive and can quickly become very expensive.