TV Guide TLC Sunday

Buying goods from the comfort of home

Buying goods from the comfort of home

Leonard and Penny offer Sheldon's old room to Raj after he is forced to move out of his apartment to save money, leading to unexpected conflict among the gang and some unwanted observations from Leonard's mother. Christine Baranski guests

Leonard, Penny and Raj settle into their new living arrangement, but Penny and Raj get along so well together that Leonard starts to feel left out. Sheldon expresses an interest in Amy's work and they begin to collaborate on a scientific project

Sheldon pushes himself to the limit when he collaborates on two scientific projects - one with Leonard and Howard, plus another with Amy - on the same day. Bernadette nears the end of her maternity leave, and looks forward to returning to work

Howard and Bernadette find it upsetting to leave baby Halley at the nursery when Bernadette returns to work at the end of her maternity leave. The gang's university colleague Bert the geologist introduces them to his attractive new girlfriend Rebecca

Leonard isn't thrilled when he finds out Penny is considering taking a new job that has been offered to her by her former boyfriend Zack. Sheldon attempts to develop his brain further by learning new skills

Amy is offered a visiting research fellowship at Princeton University, and Raj makes some new living arrangements. When the guys complete their infinite persistence gyroscope project, events spin out of control

Amy must decide whether or not to marry Sheldon and gives him an answer to his proposal. Howard and Bernadette struggle with some unexpected news. With guest stars Laurie Metcalf, Riki Lindhome and Stephen Hawking

Leonard angers the university - and the entire physics community - when he gives an embarrassing interview. Amy and Bernadette bond over having to hide their success from Sheldon and Howard. Ira Flatow and Regina King guest star

As Sheldon stresses out about picking a wedding date, Amy tries to convince him that he has a more laid-back side. Meanwhile, Raj and Stuart compete to win the heart of Bernadette's new colleague Ruchi. Swati Kapila guest stars

Sheldon and Raj turn to Bernadette for advice about their jealousy when Amy and Howard decide to collaborate on a new project. Penny and Leonard learn some new ways to manage Sheldon's irksome behaviour from an unlikely source

Sheldon competes with Wil Wheaton (guest starring as himself) for the role of the new Professor Proton when the scientist's old TV series gets a reboot. Penny looks after Halley when Howard and Bernadette are both put on bed rest

Sheldon and Bert collaborate on a research project, even though Sheldon is embarrassed to be associated with the study of geology. Penny and Bernadette coach Raj on how to navigate his fledgling relationship with Ruchi. Swati Kapila and Brian Posehn guest star

Leonard and Howard are furious when they learn that Sheldon went to work with the military behind their backs. Angered, the pair ask Kripke to help them get their own back on Sheldon, much to his annoyance. Meanwhile, Bernadette suspects that Ruchi might be trying to steal her job while she is on bed rest, so she asks Raj to investigate for her, putting him in a very awkward position. Dean Norris guest stars

The guys find a laptop that has some virtual currency on it. The only snag is, the computer belongs to Penny's ex-boyfriend Zack. Meanwhile, a seven-year-old video reveals a secret about Leonard and Penny's relationship