Not actually on board but the boarding process.
Flying out of Jeddah (Saudi Arabia) about 5 years ago. Jeddah airport - even at the best of times is a zoo with people everywhere and no seperate departure gates, just a huge open hall with doors with gate numbers above them so you can walk down the steps to get into a bus to go an find your plane.
Anyway the screens are showing gate 29 as the gate for our flight and closer to the time the press of people is getting bigger and bigger then over the PA come the announcement "Flight so and so (can't remember the number) is now boarding from gate 28, there is a swarm of people as they pick up their 20kgs of carry on baggage and push and shove their way to gate 28, then about 4 minutes after that another PA announcement "Flight so and so departing from gate 27" - another huge swarm of people down the terminal then after about 5 minutes another PA announcement "Flight so and so departing from gate 29...................except this time they had got some ropes and security up and they finally ended up with a nice long orderly queue of passengers...................never seen anything like it before - or again
