Dr. Demento is the man when it comes to funny songs.
Some of my favorites:
Wet Dream (Kip Addotta)
Pencil-Neck Geek (Freddie Blassie)Hear it (real player)
Fish Heads (Barnes & Barnes) LyricsHear it (real player) One of the "Barnes" was Billy Mumy from Lost in Space and Babylon V.
Poisoning Pigeons in the Park (Tom Lehrer) Lyrics