[lutefisk]

Sounds like a recipe for burnout. I've tried a few times picking up a new language in my free time, but since I program for work it made my days feel 3 hours longer.

I've started picking up hobbies unrelated to programming, it's much easier to spend the time learning something completely different.

[rethab]

So when I said "work on something not work related", I didn't necessarily mean "creating a side-business". It could also be studying or something. In my specific case, I try to study a specific subject each week, for which I invest 4h per week. In fact, it doesn't even have to be technical, I just try to focus on something rather than reading bits and pieces about everything on HN, Twitter, etc.