Usually, I play 0 hours. Sometimes I'll play a couple hours, but not often. I prefer spending my sparse free time coding, helping out around my preferred distro's forum, or making a little money with occasional linux-related jobs. The rest of my time is spent in bed, in class, in transit, and, when doing homework, either in trance or in pain...
I do like watching PS grow though, and do want to play more than I do. But it will have to wait until I have more time. Mostly I play it during Christmas breaks. I might play more next summer too, since I probably won't spend it at my dad's internet-less farm like I usually do.