Jokers
Though a mere civvy mesewf,
I heard from a certain Sqn Ldr about 'Jokers' on some fast jet squadrons - one was allowed to say, once during a tour, " sorry boss I'm too hung over to fly " - ie beyond the usual 100% oxygen remedy.
At the end of a tour, there was a party to use up unused Jokers.
I doubt this still goes on, or at least as overtly.
On a vaguely similar vein, remember reading about Tangmere during the war - guys were using a medicine ball in the gymn.
The padre came in, and ' joining in the fun ' mistook it for a football & gave it a mighty kick...The crack of his ankle was very audible, almost as much as the stream of filthy language which made the others wince !