My friend Stu is still upset at me for giving him Civ1. It was thanksgiving, and everyone in residence was going home, but Stu's parents were away so he was staying in residence. I gave him Civ1 at 4pm on Friday, he had dinner, then started playing at 6pm. He finally stopped playing when he feel asleep at his computer at about 3am on Saturday night (or Sunday morning, depending on how you define night/morning).
First Shift Total : 33 hours.
When he woke up at 10am on Sunday, he had some breakfast, then kept playing until about 6am on Sunday night/Monday morning at which point he feel asleep at his computer again.
Second Shift Total : A mere 20 hours.
When he woke up at noon on Monday, he had breakfast/lunch and started playing again at 1pm. When I got back at 10pm on Monday, he was still playing. At that point, Stu erased the game from his computer, gave me back the floppies and made me promise never to let him play again until final exams were over.