When digging holes in search of the dinosaur, Shawn mentions "that this is like that movie with Sigourney Weaver," and Gus cannot guess the movie. Dulé Hill actually was in this movie, Holes (2003), as Sam.
Shawn and Gus's conversations at the fruit stand about peaches are a reference to the movie Holes (2003), in which actor Dule Hill starred. Peaches are a key part of the plot of Holes.
When left with nothing as a comeback to Lassiter, Shawn says, "where'd ya get that suit? The toilet store?" Which is a quote from the movie Anchorman.
After finding the body and claiming that the culprit was a dinosaur, as the others storm off Shawn says to himself "This is not a boat accident!" This is a reference to a Richard Dreyfuss line from Jaws.
The farmhouse used in this episode was also used as Cain's house in the show Supernatural S9 Ep11. Timothy Omundson (Det. Lassiter in Psych) played Cain in Supernatural.