Not sure it's categorised as funny. But some years ago on a Kenya Airways flight NBO-AMS, after the usual "we will begin our descent to AMS shortly, weather is bla bla.." they announced this.. Not kidding..
"We apologise to the passengers that didn't get food served. Unfortunately our ground staff did not supply us with enough portions for this flight".
I did get food, though. Thank God. This wasn't exactly a short flight.