Just received a call from "704-080-8080"... which is obviously a spoofed number.  "The Numbering and Dialing Plan Within the United States" ATIS-0300076, Dec. 2008 clearly specifies the format of legitimate telephone numbers within the US.  The middle three digits are referred to as exchange codes, and the first digit of those three must be a number in the range 2 thru 9.  Therefore a zero in that field would be invalid.  It would seem that whomever this caller may be, they are likely have some nefarious purpose in mind.  Else why would they take such pains to hide their true identity?  Since it is clearly a spoofed caller ID, I have blocked this number.