Free time? What is that?
That's pretty much how I feel, but my definitions may be off. I would have more free time if I knew how to stop adding things to my plate!
A free 30 minutes? That's generally not what occurs. I suppose what I most often do is I pull out the cell phone and call some friends who I haven't talked to in a while, and hope that one of them is in the middle of a similar free 30 minute period. I never got into reading, but I've done some writing. For a while I had a project where I was working on what I call a "vehicle diary" which is every vehicle (car, motorcycle, and now airplane) I've had enough experience with the write something worthwhile about. Mostly it's a collection of stories, though. The rest of the time, I think. There are enough thought exercises I go through that I always have something to think about.
What will happen on occasion is I'll get plans cancelled and have a free weekend. Then I'll normally sit on the computer for a bit and think about what I want to do for a while. This usually results in the start of some large project, or actually diving into some other project. For example, two weekends back I didn't have any plans. While sitting at my computer, I decided I was going to start on some major yard projects I had planned. So, I went to Lowes, bought 31 trees, and planted them. Then I bought 500 railroad ties that I'm going to build a wall out of. Unfortunately, I can't build the wall myself. I'll need to get some friends over to help me on that.
Sometime this winter when I have one of those Saturdays, I'll tear into the 6.0L V12 I have sitting in my basement that I'm intending on rebuilding for my Jag. Eventually I need to figure out whether I'm turbocharging it or leaving it naturally aspirated with some warmed over cams and port the heads a bit, plus my intake manifold design I've been working on (gotta fabricate that one of these days...).