MatJ’s answer reminded me of time...
I used to work for an organ festival (the instrument not the um, well you know) and there were all sorts of pranks we used to inflict on the normally slightly odd young organists (I hasten to add here that I do know lots of normal, well adjusted organists, but there does seem to high number of them that think everyone wants to see slides shows of various organ pipes from around Europe- no, tragically, I’m not making this up).

Anyway. Being very keen organists they would sign up for the chance to play the, apparently, very special awesome organ in the chapel where the festival was based. As they all wanted to do this the practise sessions lasted well into the night where the they would sit in the dark church and play til 2am.
As we knew the chapel fairly well we knew a) where the light/fuses were, and b) how to work the radio mic system they had there.
It was funny to see how scared the organists would get when plunged them into utter blackness and scream into the mic “GET OUT! YOU ARE NOT WORTHY TO BE IN MY PRESENCE! BEGON OR FOREVER BE CONDEMNED TO THE DEPTHS OF HELL...”
We got forced to stop after one wet himself though....
(ab1kenobe, Mon 5 Sep 2011, 16:33, 2 replies)

What do you mean, you're "going to the pub"?!
I haven't finished showing you all the pictures of the 16' contrabass flute pipes with overhanging Tierce pipes on that 1984 Frobenius yet! Totally the best organ in the Midlands, and I haven't even got onto the charming little peculiarities of small one-manual pump organs yet!

/Was an organist. Know the geekery to which you refer.
(The Empress it seems you CAN polish a turd!, Mon 5 Sep 2011, 21:44, closed)

I once had a summer job
restoring Spanish Baroque/Renaissance organs. They sounded (and indeed smelled) like death even after we'd finished with them.
(grandmasterfluffles Come to my Armageddon party on, Tue 6 Sep 2011, 3:03, closed)