Finding time for side projects and keeping marketable skills current

I'm six years into a CS-related career and I can't complain. I chose an industry that provides not only big salaries in a somewhat-low COL area, but quite a bit of stability due to the nature of the work and the restrictions on who can be hired to get it done.

Anyway, I'm finding it hard to get going on side projects and I'm finding it harder to keep my marketable skills current. After my wife and I get our two kids to bed at night I have at most 3 or so hours to myself— on a good day.

And in that 3 or so hours I have to choose between hacking on a fun side project in a domain of my liking (e.g., low-level C and asm hacking; image/video restoration filters) or learning a boring-as-hell skill (e.g., Apache Spark) I can market in my industry.

On most days I can't decide and wind up focusing on one of my other hobbies instead: 35mm film preservation; collecting Laserdiscs. Three hours flies by. Sleep. Rinse. Repeat.

So I really haven't gotten anything done. I'm a bit better of a programmer compared to myself in 2010 and I know a bit more CS, but the last project I worked on that I was truly proud of was my undergrad thesis.

The problem is that I have the ambition. It's there. Hell, it's swelling inside of me, but I just don't know what to do. I have this desire to hack up something I'm proud of, but with such a limited amount of time I feel like I should be spending it on something that will help me keep my job long-term.

And I'm doing neither.

And I'm not learning more CS which I would prefer to either one.

And I feel like I'm decaying into a husk of my former self.

Help?