A little history on Jenny from Wikipedia:
“867-5309/Jenny” is a song written by Alex Call and Jim Keller and performed by Tommy Tutone that was released on the album Tommy Tutone 2, on the Columbia Records label. It peaked at #4 on the Billboard Hot 100 chart and #1 on the Billboard Top Tracks chart in 1982 (see 1982 in music). Co-writer Call came up with both “Jenny” and the telephone number and completed the song with Keller.
The song caused a fad of people dialing 867-5309 and asking for “Jenny”.
Now some people got the famous Jenny phone number and are recording the messages that come in.