I slept through a full day once when I was dreadfully sick and I had stayed up for twenty-four hours the day before. I woke up at eight o'clock at night, ate some quick soup, and crashed back down again. I remember that I just bought a Treecko plushie, and woke up with it attached to my cheek.
Now, the latest that I sleep is two in the afternoon. Work keeps me from getting long amounts of sleep. On the plus side, I sleep deeper than I used to, so I am more rested. Except for now, when my alarm buzzes me awake in the middle of a dream. Dang school keeps me from getting good sleep.
So, yes, the latest that I woke up was eight o'clock at night.