Well, at work I spend about 6-8 hours depending on what I'm doing in my project cycle, whether I have meetings, etc.

At home, I tend to tinker with game engines and level editors, but don't have any solid basis. Usually it's about 4 more hours or so unless I get completely entrenched in what I'm working on.

On weekends, I tend to go completely offline and just enjoy myself. I go out with friends, see movies, go hiking, do anything so that I'm refreshed with "me time" for the week ahead.