On a side note a co-worker got me pretty good the other night.  If a device on one of the networks we monitor has a failure it forces an audible alarm.   We use a .wav file of a siren to indicate a problem.  It's pretty damn loud to get our attention.
The other night at about 4am (my shift is always 6pm - 6am and I am always in the building alone) the shrill piercing scream of a woman came blasting through the alarm speakers, it lasted a seemingly endless 5 seconds.  Needless to say I jumped about 2 feet off of my chair.  About 20 seconds later an email came into our company central inbox, it said simply; "How'd you like the new alarm .wav file?? Hehehehe!!!"