Been there, done that.
The best one I had was at a site where we didn't *really* have a LAN room - this was, oh, I dunno, maybe 25 years ago now.
We had a small partitioned area into which we had stuck several racks. No raised floor, just sitting on the carpet.
Because the air conditioning was inadequate for the progressively larger and larger amount of kit being put into the room (this was the very beginning of "corporate LAN's in Australia - Australia's largest Telco, Novell 2.1, 10Base2 Coax networks, 286 PC's as clients, so everything was *huge*), the powers-that-be had a couple of stand alone air conditioning units connected in the room.
Trouble is, they were connected to the building chillers for cold water supply.
This all went very well - air con kept the room to a level where nothing blew up, and all was good.
Until the semi-annual "cooling tower cleanout" was done on the building chillers.
Now, I don't know if you've ever been a party to this, but back then part of the process was completely replacing the chiller water - after purging the system by adding an *extremely* strong caustic into the existing water to get rid of any cr*p which may have grown or infected the system.
You can see where I'm going with this, right?
Our stand-alone systems were linked to the chillers via *copper* piping - and the caustic promptly did its best and ate *holes* into the pipe at the joints in our computer room where it pooled and took a bit to get forced back out by the pressure.
Cue *large* amounts of contaminated, caustic, bright GREEN water flooding into the floor of our "computer room". Seems the partitioning was all-but water tight too - the only leaks were under the door, and those only minor because of the door seal.
All this happened, of course, before we got in for the morning - I arrived to find 3 and a half inches of water lapping at the bottom of the rack with out (then) very expensive HP router in it, and our several (then) even more expensive servers being mounted 4 inches from the ground.
I've never thrown a circuit breaker so fast in my life. I didn't care what happened to non-cached data on the servers (turns out I only corrupted a single bTrieve database, which happened on average twice a week anyway), I was only filled with an urge to NOT see the smoke being released from the kit.
Luckily, the water didn't actually get inside any of the cases - although it was touch and go - because the air con guys noticed the loss of water and came down the building floor-by-floor until they found out where it was going, but many, MANY bad words were said by me as to the advisability of checking they wouldn't damage anything before just dumping kilos of caustic cr*p into a water supply next time!
