I'm looking for stories where you played almost uninterrupted... If you went to school or work in the middle and left it paused, it's 2 sittings. Going to the bathroom or eating something is okay, though, of course.
Mine is definitely Zelda: LTTP SNES version. I once played it start to finish in one sitting without saving once when I was 15 or so. The point was to get a 0 under my file... I think it took me 6 hours.
I'm pretty sure I also did it with one of my Super Metroid speed runs, but that only took like an hour or two.