Two of my favourite "Overheard on the R/T" conversations:-
A/c: "We're a flight of 2 A10s at low level routing past XYZ request Radar Information, and we're sorry but we've forgotten our formation callsign."
ATC (with relish): "No problem. Adopt callsigns Stupid One and Stupid Two"
In the 1980s, when East Anglia was base to numerous A10s, a USAF tanker would regular fly on Towline 6. There it would service a seemingly endless stream of A10 pairs and 4-ships using callsigns such as 'Reno', 'Thunder', 'Rocky', 'Warthog' et al. One day a more unusual callsign checked in for AAR:
A10 Lead:- "Asshole check."
A10 Wingman:- "Two."
A10 Lead:- "Neatishead, this is Asshole section, two A10s for Towline 6."
GCI:- "Station calling Neatishead, confirm callsign?"
A10 Lead:- "Asshole section, Sir."
GCI:- "Say reason for callsign?"
A10 Lead:- "We were late for the brief, Sir."