Well, let's see. There's the contractor that was in to change the blown light bulbs in the machine room. On the way out, he leaned his ladder against the wall near the door. And, it just so happens that one of the steps was at the exact correct height to push that big red EPO button. CLUNK! Followed by the sound of total silence in a machine room with 15+ mainframes. Ohoh!
So, the obvious solution was to put a protective cover around the big red EPO button. So, a contractor was called in to do it. He opens the door, brings his ladder in (despite the fact that he really didn't even need a ladder!), leans it against the wall next to the door....CLUNK! Ohoh!
As for backups, the I/T group assured us that the system disks were being backed up to tape every night. A few months in, someone asked them for exact details, and they gladly told us which two tapes the system disks were being backed up to. We eventually realized that when they said "system disks", they meant the two disks with the operating system on it, not the 40+ disks with the user data on them that were attached to the system! Whoopsie!
Then, there was the time that the automated backup job would run overnight, and back user data up to tape. Unfortunately, the amount of user data had eventually grown to the point where it wouldn't fit on the tapes allocated. So, the night operations staff simply grabbed the needed tapes from the scratch tape pool, and satisfied the backup tape requests with those tapes. Oh, and, of course, as soon as the backup jobs were finished, they returned the tapes to the scratch tape pool! Yeah, I lost some data from that one, but it was almost worth it for hearing the explanation from the I/T installation manager.
Let's see, there was that incident where the people on the third floor called the machine room on the fourth floor to ask them why there was a stream of water coming through their ceiling. That was about the same time that the operations staff noticed that one of the mainframes had started failing. Can you say "Broken chilled water line?". Ohoh!
Then, there was that time I requested a tape from the automated tape librarian. The tape was assigned to me, mounted, and I dumped a sizable quantity of data to it. I then unmounted the tape, but kept it assigned to me. A month later, when I went to retrieve the data, I requested that the tape be mounted. After an hour of waiting, tape operations finally called me up: "We keep seeing this mount request for a tape for you..." "Correct." "only, we don't have a tape with that volume serial. Furthermore, we've never had a tape with that volume serial." "Err, how did the automated tape librarian assign it to me last month, and how was it mounted then, and how did I use it, if it doesn't exist?" "Ohoh!" (Yeah, I had a LOT of *fun* with tapes.).
Then, there was that lightning strike. Did you know that lightning can make CRT displays show funny colours for days afterwards? Did you know that lightning can also make pretty colours inside of computers, routers, and just about anything else? I'm still trying to clean up that mess. :-(
There are always those amusing, and somewhat rhythmic, yet very unmusical sounds from disk drives as they're dieing a horrible death: "Screeeee-CLUNK-CLICK-Screeeee-CLUNK-CLICK-Screeeee-CLUNK-CLICK..."
As for sensations, who can forget the smell of hot electrolytic capacitor electrolyte from inside a system. Can you say "Bulged capacitor syndrome"? I can! :-(
I could go on for hours. :-(