While I have no wish to follow on the "4 yorkshiremen" sketch and try to "top" anyone else, I can, in total honesty, say that I once, due a shortage of personnel, had to work, along with a few others, a shift pattern that consisted of 72hrs on, 72hrs off.
This went on for about 6 weeks until the manning situation improved.
I'm not saying it was hard, or that I didn't sleep at all during my 72hrs "on", but I am saying that it actually happened......
Tell youngsters that today - and they won't believe you...!