Taceval
When 204 (Shackleton) Sqn was based at Honington, we had the national SAR task, and so were "excused Taceval." The best bit was that during Taceval, the Officers' Mess bar was open 24 hours a day. Better still, it was the nominated 204 Sqn refuge!
How we loved Tacevals and Minivals (apart from the duty SAR Crew, of course.)