I've performed many recitals on one particular organ (which shall remain nameless) that seems to be jinxed. Atfive differentrecitals one of these things happened:
- Swell to Choir shorted out, and had to be permanently soldered "on" minutes before the recital.
- The arm that moved the Swell shutters became detached and was swinging wildly about the chamber; the temporary solution was to nail downthe Swell shoe- of course I wasperformingromantic music.
- The ending of my recital was spoiled when I couldn't use the Chamade - the low D-flat was nowhere near the right pitch, and I couldn't avoid playing that note. That was the only pipe that had a problem.
- Another recital was spoiled when I couldn't get the tutti button to engage;A major work was the sole feature of this recital, and at the very end (the "big finish") the 32' reed and chamade were to have come on. I kept hitting the tutti during the last line of music - it would disengageevery timeI took my finger or toeoff of the tutti button! [:@] I finally got it to lock "on", but I was very distracted.
- The pedal light burned out during the service immediately prior to my recital, so I was obliged to guess where the toe pistons were.[/list]
There are other organs too, and some near-disasters (sorry if a bit O.T.): I played a very British program (with Tubas blazing, etc...) on an organ with a lovely Tuba Mirabilis. When I arrived for my first practice session I was told "Oh, our Solo division is being repaired - no Tuba." [:O]
At yet another venue I had prepared a recital that contained an transcription of a symphony movement - lots of registration changes. When I arrived at the venue the combination action was explained to me: There were over 2,000 memory settings; you set each registration change as you go. "Very good", I thought...
The problem was that it was a blind system that didn't move any stops. [:O] The other problem was that it could only go forwards, so if you hit a button too soon, you were out of luck! It was also very tricky to move it to any given registration as it was sequential, and slow.
The deal-breaker was that as long as the combination system was engaged, manual registering was disabled. "Forget that!" I said!
We did the recital with two registrants. They were very busy. 
At my own church I did an all-Vierne program. We had spent a couple days tuning the organ to a state of near perfection - it sounded absolutely magnificent! The day of the recital we had a huge heat wave. Unfortunately, the boiler was programmed to come on and nobody could find the fellow who knew how to pull the plug properly. It was probably near 100 degrees in the room, and the organ sounded like a sad accordion. 
We were able to re-tune the reeds in a huge hurry, but I was wiped out mentally/emotionally - and I was wiped out physically from another full day of tuning - and the heat.
I have a recording of that recital - the organ didn't sound quite so bad;only one Trompette pipe flew off pitch. I know just how it felt.