Electronics, i just enjoy repairing broken things, it doesnt really matter what the thing or issue is, i just enjoy solving the puzzle if you will
Music, i dont play an instrument or anything but unlike many people i spend time just listening to music, not as a background to other tasks but actually sitting and enjoying it or looking for new stuff
Travel, i tend to spend a good amount of that time we all spend idly browsing the net to look for info on places i plan to travel to. In recent years i go to japan once a year so i spend time looking for things to do/see when im there, it may sound excessive but anyone whos been on holiday with me will tell you that it pays off
I should strive for more "active" hobbies. I have friends who go to the rock-climbing gym fairly often.
- Hardware tinkering, picked that up while I was in a similar situation years ago. It can be fun to just solder along and program non-work things with low-level abstractions sometimes.
- Sewing, honestly not sure why I started that but it's a nice indoor hobby away from the PC.
- Hiking and the gym (weight lifting and crossfit mostly), for obvious reasons (nature and movement, especially after those debugging days). Both took some getting used to and integrate timewise but I couldn't live without anymore.