He's dead, Jim

The show: Family Guy
The episode: "Not All Dogs Go To Heaven"
What happened: The Griffins go to a Star Trek convention in Rhode Island. A flashback shows Peter at a previous convention asking Shatner about the episode in which he killed his wife (by drowning her in a pool in 1999).
Why it makes no sense: While it's true that Peter has trouble distinguishing reality from television (as has been abundantly shown throughout the series), he couldn't possibly ask William Shatner about his wife who died in 1999, or about anything else, because in the Family Guy universe, William Shatner himself died in 1999 when Meg accidentally ran him over with the Griffin family car. That episode, "I Never Met The Dead Man," has to take place prior to 2000 (before "Holy Crap"). This episode has to take place after 2000. The flashback could be prior to 2000, but after being asked such a tacky, thoughtless question at a convention, do you really think William Shatner would care to hang out with Peter as he does in "I Never Met The Dead Man"?
There's also the small matter of where exactly in Rhode Island the current Star Trek convention takes place at. The establishing shots emphasize that it's in Providence, but Brian later says that it's in Quahog. But since the show has been inconsistent as to the exact location of the fictional town in Rhode Island, we're just gonna have to let this one go.