Factual error: Carol and Frank leave for a romantic weekend and Dana begins to tutor Rich for a test in English Literature. When Frank and Carol return on Sunday Rich has not only studied for the test but also TAKEN the test and gotten the results back. How is that possible over a weekend?
Other: When Black Bart repeats his line about how sheriff Frank is a washed up, yellow bellied, gin guzzling pile of buffalo chips his French accent is gone and the actor's real American accent is heard.
Deliberate "mistake": When Frank tosses the cards in the end they all hit the camera very obviously. When the episode first aired the last scene was in 3D, which is why he tosses them directly at the camera like that.