The movie Toy Story is mentioned by Raj just before he, Leonard and Howard approach Mary Cooper's house. Mary Cooper is played by Laurie Metcalf, who did the voice of Andy's mother in Toy Story and its sequels.
When Sheldon's mother claims that her prayer group kept him safe, he criticizes her logic as being "post hoc ergo propter hoc." The Latin translates as "after this therefore because of this." Sheldon is pointing out that the group's praying for him and his safety cannot be taken as cause and effect.