TV Guide TLC Sunday

Leonard and Sheldon disagree over whether to continue holding their regular Roommate Agreement meetings, with Leonard suggesting they are no longer required, while Sheldon believes they are still essential. As the pair's squabble quickly escalates into a full-blown argument, the rest of their friends turn up for a planned Game of Thrones viewing party, and end up taking sides in the dispute - resulting in two warring factions taking up residence in 4A and 4B. Comedy, starring Johnny Galecki and Jim Parsons

The gang goes to a bar and runs into Penny's old boyfriend Zack, while Bernadette is left to spend the evening with Sheldon when she cannot go wine tasting with the others. Elsewhere, things do not go to plan when Raj introduces his new girlfriend, Claire. Comedy, starring Johnny Galecki, Jim Parsons and Kaley Cuoco

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

Conflict arises when Leonard's newly divorced parents and Sheldon's devoutly religious mother are all in town at the same time. And when Howard and Raj are contacted about the guidance system they've developed, they assume that the government is out to get them. Laurie Metcalf, Christine Baranski and Judd Hirsch guest star

The friends struggle through an awkward morning after Sheldon's mother and Leonard's father share an evening together. Penny's family arrives in town to attend Penny and Leonard's second wedding ceremony. Keith Carradine, Laurie Metcalf, Christine Baranski and Judd Hirsch guest star

Howard has a meeting with Colonel Williams, a representative from the US air force's department of material command, about the gyroscope he invented with Leonard and Sheldon. Penny accidentally reveals that Bernadette is pregnant to their colleagues at work. Dean Norris guest stars

Tensions rise when the guys struggle to complete their Air Force project on time and are forced to work around the clock - leaving Sheldon fighting to stay awake. Penny and Amy attend a university gathering at the home of Bert the geologist. Raj learns Bernadette's true feelings about her pregnancy when he helps her to clear out the spare room for a nursery

Howard and Bernadette decide they do not want to know the gender of their unborn child, but are upset when they hear Raj has found out before they have. After Amy's apartment floods, she proposes a cohabitation experiment with Sheldon to stay with him while her apartment undergoes repairs