In which Family Guy episode do they go to a Star Trek convention?

The Family Guy episode where they go to a Star Trek convention is "Road to the Multiverse" (Season 6, Episode 1).

In this episode, Peter, Brian, and Stewie travel to a parallel universe, where they end up at a Star Trek convention. The episode features many Star Trek references and jokes, including Peter dressing up as a "Borg" and attending a panel discussion.