Aeropause posts that a recent episode of the show features a Grand Theft Auto parody. From the original post:
Last night's episode of The Simpsons had Bart seeing a psychologist to try and figure out what motivated him to tell a ghost story about a school lunchroom cook that beheaded and made soup from kids many years ago...
Bart initially resists the psychologist, so she feigns disinterest, saying that since she gets paid by the school either way, they might as well play videogames instead. What's the videogame? Why it's Death Kill City II: Death Kill Stories. The box art even mimics the style of Liberty City Stories and Vice City Stories.
Bart proceeds to gleefully eradicate all of humanity in the videogame and the psychologist takes notes.