Back in 1970s there was a case where all three crew of a BOAC B707 fell asleep on route to Bermuda. The aircraft did a gentle 180 to head back east, but an alert cabin steward noticed the sun was on the wrong side of the aircraft and woke up the crew. Strong coffee was administered frequently until arrival!
Later in BA during crew fatigue trials we had a B747 Classic flying with an egg timer fitted under the mag compass. It was supposed to be set at 30 mins, and rewound as soon as it went off. If I remember rightly the egg timer ended up in the trash bin!
