The Big Bang Theory: The Line Substitution Solution

Sheldon discovers a surprise screening of The Avengers is scheduled at a local cinema, complete with a Q&A session with the film's director, Joss Whedon. However, the event just happens to clash with time he'd planned to spend with Amy, so he decides to pay Stuart to be his subtitute for the afternoon while he and the other boys immerse themselves in Marvel superheroics. Meanwhile, Leonard's mother Beverly arrives in town for an extended visit, and Penny takes the opportunity to bond with her new mother-in-law - and to make up for not inviting her to the wedding. Comedy, guest starring Christine Baranski