Some time ago, I told the story of how one employee's phone received calls intended for a local radio station's contest line due to people dialing seven digits instead of ten and defaulting to the wrong area code.
Upon reading that story, a colleague of mine pointed out that one of the conference rooms in his building has a similar problem. The direct line for the conference room is identical to the request line for a local radio station, save for the area code. People who work in the building know never to answer the phone in that conference room.
(Although apparently there have been a couple of pranks involving the call-forwarding function on the conference room telephone.)