Another physicist speaks...
Wow, a lot of physicists on these boards. I wonder why?
I got my PhD (Piled Higher and Deeper) from University of Michigan in 1999 in cosmology. I was lucky to have a great circle of gaming friends there, and had no problem making time for a weekly campaign--I ran one for a couple of years while I was getting through the coursework and then played in one until I finished.
I find it's much harder to game now that I and all my friends have full-time jobs--we're more tired in the evenings and weekends are doubly precious for spending time with the family--it's hard to schedule a few hours together. I still do board games from time to time though.
But having said that, it depends vastly, hugely, on the department. Every department, no matter what the subject, has its own culture and requires different things of its students. So make sure you talk to a lot of other graduate students when you're scouting schools, and find out how harassed they're feeling. Coursework+TA/RA makes a full-time job in theory, but there are a lot of schools out there that expect 60-80 hours a week, or more, out of there students. Find a school where the students are unionized, and you'll be sitting pretty. Find a school where they're treated like slaves, and you'll end up as one too.
Remember, you're spending 2-6 years there (depending on whether you decide to pursue the doctorate), so make sure it's a place you'll enjoy yourself at. Grad school is *not* worth it if you're not having fun, and for most people studying the subject matter is fun but not 100% fulfilling.
The thesis was not a problem for me, since I was already producing papers in the course of my research. Experimentalists who spend years designing and building an apparatus and making measurements have more trouble because they haven't had the practice. I imagine in CS you'll be putting out papers on the 6-mo to a year time scale rather than the 2-4 year time scale, so it shouldn't be an issue. More and more dissertations these days follow the anthology format.
Good luck, choose well, and have fun. Grad school was a very good experience for me, and it can be for you too.
--Ben