Obtain a copy of a magazine that your intended victim wouldn't be caught dead reading.  Frederick's lingerie catalog is good for prudes.  A wrestling fanzine is just the thing for snooty highbrow types.  Forge a mailing label with the victim's name and any plausible address on it.  Glue the label to the publication.  Place the publication, apparently subscribed to by the nimrod, in the staff lunchroom for co-workers to marvel at.  You can't tell which way a train has gone by looking at the tracks, and if you're careful enough, there'll be no way to track you down either.