Got to agree with Mirabeau, I had the situation after a 9 hour flight from the middle east, put the a/c to bed, catch a cab to the hotel, check in and order some food only to get a phone call 15 mins later from the boss that he needs to go back to the middle east and can we have the aircraft ready in 2 hours !!!!.
Happens all the time to us but we have not yet had the balls to try power napping in turn so when atc is looking at all the maggots on the screen, guess which one is well rested and safe to make that approach in bad weather with g/s out so loc only etc.