Factual error: Ray, Sara, and Kendra are left behind in 1958. However, 10 weeks later Sara and Kendra are playing the board game "The Game of Life." The modern version, as seen, didn't come out until 1960 (previously it was called The Checkered Game of Life and doesn't resemble the modern version).
Trivia: Not quite a mistake given the fictitious nature of the show; but in 1960, as a college physics professor, Ray makes a comment indicating one of the guys in his class is Bill Gates' father. Bill Gates' proper name is William Henry Gates III, and the man in class would be William Henry Gates II (or William Gates Jr.), which should have been enough of a clue for Ray who this man was. However, Bill Gates' father graduated from law school in 1950 and would have been 35 in 1960, not some young college kid taking a physics class as shown.