Seriously, I've been thinking really hard about this question. And I find myself going to my roots more often. Moved away from "nerdy" IT when I got into university, being a "career man". But then the unavoidable constant stress kicked in and I got back to my hobbies:
1) Configuring and building PCs. It is like LEGO. So relaxing. But it's still technical.
2) Tinkering with linux installations and packages, trying to discern what EVERY package does. And SystemD OS that now runs the entire universe.
3) Photography. There is nothing more relaxing to go deep into a forest or rural areas where there are NO F**KING PEOPLE. And then take pictures, coz again it's still technical. It's relaxing while being technical at the same time.