Black and Tan: A Crime of Fashion - S2-E15
Continuity mistake: After picking up the papers and book that were dropped, Shawn is holding and looking through the book, and Emily is holding the papers. At one point Emily takes the book from Shawn and the papers she was holding disappear.
Black and Tan: A Crime of Fashion - S2-E15
Continuity mistake: When Shawn scares Emily she drops the papers and book she is holding. The book is on the bottom, but when Shawn helps her pick them up the book is on the top.
Black and Tan: A Crime of Fashion - S2-E15
Factual error: In the flashback at the beginning of the episode, Shawn is wearing a Knight Rider T-shirt. This flashback takes place in the 80's, but the art printed on the T-shirt is a picture-perfect copy of the cover art from the US DVD release of Knight Rider Season 3 - this DVD set (and the cover art style/arrangement) was not released until 2006: http://en.wikipedia.org/wiki/Knight_Rider_%28season_3%29.
Chosen answer: "Psych: The Musical" was supposed to air during the regular season 7 schedule, before Chief Vick is suspended and Jules discovers Shawn's lie, but the network decided to push it back to air as a special episode, sort of as a tie in with the holiday season and a lead in to season 8, which was to begin only a couple of months later.