VoIP News reports that a NASA Blunder Leads To VoIP Shutdown. You know, the good thing about VoIP from a support perspective is that if the phones go out, nobody can call you to report the problem. :-)
The article cites the cause of the error as being an administrator inadvertently deleting the entire user directory. Of course these sorts of things could potentially happen in the non-VoIP world, but don't be surprised if this event is portrayed as yet another reason why VoIP is evil.