52 hours of final fantasy 8, i'm serious. last ~10 hours were just grinding, hitting the same button over and over again. maybe i fell asleep and didn't notice.

Probs about 2 days on wcw mayhem.
I literally did a full weekend

82 hours, I wanted to make it to 100, but I fell asleep.

I think that is legitimately one of the longest gaming sessions of Duck Hunt that anyone has ever had.

I want to say 18 hours. Like 9 am on a Saturday straight til 3 am. Just a beer run, food, and bathroom to break it up, might have jumped on the forums for 30 min somewhere in there.

I have done that timeframe a few times. Most recently with Bloodborne, but I also did it several times with Guild Wars 2(I was into WvW and I used to command alot and I would play through the different timezones so we would not lose our keeps and shit, lol)

About 12 hours of Assassin's Creed IV, I think.

I feel like an oldie now. Has to be between Pokemon Red, GT 3 and Donkey Kong 64. Somewhere around 6-8 hours no more. These days, 2-3 hours is too much for me.

10 hours straight of Brawl's Subspace Emissary.

I can't play for anywhere near as long as some of you lot due to work, other commitments etc. But did do about 6 hours straight once on the day I bought the original Jak And Daxter for the PS2. That game was so good. Its was the best platformer I'd ever played, even topping Mario64 (at the time.)

About 24 hours I think...

~11 Hours with Spore and ~8.5 Hours with Europa Universalis.