Okay, sad as this sounds I actually did once start playing Flight Sim on a flight from SFO-DEN, and it was back in early 98. I got bored after a few minutes (and felt a bit silly), shut down the laptop, and switched to a book.

A few minutes later, a very loud beeping alarm was heard throughout the cabin, followed shortly afterwards by an announcement that we had to make an emergency landing. (Evidently smoke from an some kind of electrical bus in the cockpit had set off the alarms, and the fire/smoke was extinguished well before a safe landing was made in SLC, though not before the alarms went off a couple more times. It was on a Frontier Airlines 737, if I recall correctly). Only time I've ever experienced an emergency landing that wasn't for some sort of medical reason.

On a vaguely related note, the first time I ever got to fly in the upstairs cabin of a (UA) 747-200, I made sure to watch a DVD of Airport 75. (Fortunately that flight was uneventful.)