Other than doing a little socializing, I write what want to write, or else write I think needs to be written.
Writing is not a hobby for me most of the time. Most of the time I write what someone else wants me to write, or else I write what otherwise earns me some income. With my free-time writing I either write for enjoyment or else write from my "personal agenda" - not usually because I want to write from a personal agenda for some reason, like venting or clearing my head. Instead, I use my ability to write to try to share what I've learned and what I think, if a few more people would learn it, might help "make the world a better place". I don't mean to come across as "trying to be lofty" or "do-gooder". It's just that there are so many things I've learned over the course of my not-so-brief lifetime that I really hate to waste all those hard-earned lessons by a. keeping them to myself, and b. letting others learn them the hard way - or never learn what might be useful to them in their own life.
I do with reading what I do with writing: Sometimes it's for work. Sometimes for enjoyment. Sometimes to learn something. Then, as with writing, sometimes it's just for my own enjoyment.
So for me, writing and reading are both non-free-time things for me and free-time things for me. They're work. They're hobby. They're personal "passions". With those being essentially the only thing I do for either work or hobby, there are spin-off things that take my time - such as learning new programs, dabbling in a little photography or drawing as part of some of writing efforts; studying up on/dabbling-and-muddling in things I need to learn for either work or free-time writing.
That sounds pretty dull and un-interesting to a lot of people, including me; but between the things I've mentioned and the fact that I have the usual responsibilities as well as a close family, a few close friends, and keeping generally informed in life; I don't have other free time or even interest in doing much more in terms of a hobby. It may not be exciting or interesting to most people, but I like knowing that I make really good use of my time.
When I want to just relax and take a break (or kill boredom) I come to "Answers" here and see what I can come up with. Technically, I suppose it's more writing.
I kind of feel bad that I don't have an unrelated hobby, but then again I get a lot of different things from that whole mucked up mix of the work/free-time-type-of-stuff that I do. :)