This brings to
mind one of the old practical jokes, which can no longer be
 used on modern systems...
  
 A couple years back someone on this list posted an HP control sequence for
 changing the READY message on HP printers. So I wrote a script that found
 every printer on campus, changed the READY message to INSERT 5 CENTS, ran
 the script on April Fools' day and sent a message to the campus announcement
 echo saying that all printers now would require a five cents' per page charge
 with charge accounts required from all offices (coin acceptors to be
 installed that same day). I nearly got in trouble with the Financial VP but
 it was a great joke! I still have some archived voice mail from people who
 took the joke completely seriously :-) 
 
Sounds like the April Fools joke I worked out with a DEC RP06 disk drive
power sequence cable and a 75 cents coin box from a commercial washing
machine.  This joke requires a very cooperative customer. 8-)
Your RP06 doesn't spin up...
Call field service...
I respond and drop 3 quarters in the machine which connects the power
sequence leads...
Close service call.
Of course there was a Memorex guy who got fired when DEC found him
shipping oem'd 677's (RP06's) to DEC with sample boxes of Tide in them.
--Bill