Voltaire is a filk artist who is...uh...colorful. He's got a really interesting kind of mix between Mariachi band, and what I can only describe as eastern European folk.
Zombie Prostitute (NSFW...like obviously)
USS Make Some Sh*t Up (makes vicious fun of Star Trek, also NSFW for language)
Also on the Zombie kick, the WAY more SFW, less funny but really fun zombie song I know is by a band called No More Kings.
Zombie Me
Also pure dumb fun Jump In is also REALLY fun and a nice homage to Knight Rider.