I recently was up until after 1am playing Twilight Princess, though it was a Saturday night so I didn't have to worry about getting up for work the next morning. The latest I ever stayed up playing a game was Super Mario 64 back in high school. I remember I was in the Dry Dry Desert pyramid when I looked at the clock and saw it was nearly 3am.
I generally don't play games late at night anymore, cause I tend to have a hard time falling asleep after a big play session. Either that, or I'm just getting old *L*.