I'd forgotten all about this, but just came across the MP3 buried in the depths of WFMU's website. I should never have lost track of it, especially since I'm the one who put it there in 2004.
From my original WFMU post:
Throughout the mid and late 80s, the APRC (Alternative Press & Radio Council) ran a 24 hour concert info hotline (212-OPEC-SID) that would give bridge and tunnelers without easy access to resources like The Village Voice a pre-recorded rundown of all the punky rock shows going on for the week. Someone who is remembered only as "The Phantom Phone Hacker" would sometimes dial into the system (really just a primitive cassette-based answering machine) and change the outgoing message to feature some pretty unlikely lineups...[Download MP3]
These recordings were originally gathered on one of the old Jersey Beat cassette comps, but this MP3 was spliced together and edited for radio airplay. Yes, it's stupid, but it's also a funny relic from an era of primitive technology.