Most recently a little bit late to work playing Katamari Damacy, and before that, Simpsons Hit and Run ['just one more mission'].
Back in college, used to stay up all night playing Vincents Hollow, a text MUD--one time I quit playing at 830 AM, got 1/2 hour nap, quick shower, grabbed some breakfast from the dining hall, made it to my 1000 class at about 1015. Slept through it. After that I just said Screw it, I'll skip class if I ever did that again.