My record was 12 hours on GTA: San Andreas, and that was alternating with another person every time or every other time we died. And with all the jackass ways to kill yourself in that game it's actually pretty often. Jumping off the walls of buildings on a bicycle with the super jump cheat was awesome. But still, that was with another person alternating. By myself I think the longest I've played a game in one sitting was maybe four or five hours with Oblivion and Fallout 3. After that I physically can't do it, in a contest setting maybe I could muster up eight hours, but that would be stretching it. I get tired of staring at a screen, my eyes get sore, and I'm getting bored with a game, no matter how great it is after an hour or two. Not the game overall, just playing it for the time being.