In the 1980s, a song "867-5309/Jenny" by the band Tommy Tutone sparked a fad of people dialing the phone number asking for the girl named Jenny.

A few years back, someone called that number on every single area codes in the United States, and recorded the result: Link - via GorillaMask

Other Links: Tommy Tutone Song Drove Phone Companies Nuts at Snopes | 867-5309/Jenny [wiki]