Tom Mabe pranks a telemarketer.
As it was played on a radio show (includes text of the convo)
http://www.youtube.com/watch?v=kAb8vGSRBoE
Without the radio show.
http://www.youtube.com/watch?v=-7OgWcwgB50
I heard that on Art Bell. Probably during one of his many unretirements.