Four days straight playing Super Mario World. I was about twelve at the time, and we couldn't save the game because the battery had become disloged (or that's what my dad said). I wanted to see how it ended. Not only did I beat the game, but I beat all the special stages, too. Which was wierd, because after you do, everything looks like Mario. What kind of a reward is that?
So four days is about 96 hours, right...let's say 100, because I remember being almost finished and Dad coming up to me and saying, "Buddy, it's been four days. You done yet?"
On a completely unrelated note, I have twice stayed up for over a week. Don't ask; both of them are very long stories.
Apologies for leaving all of you in the dust. You shouldn't have asked.