"The Infestation Hypothesis

A fight between Sheldon and Penny leaves Amy caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya.

The Chair

A fight between Sheldon and Penny (Kaley Cuoco, right) leaves Amy (Mayim Bialik, left) caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya, on THE BIG BANG THEORY. Photo: Adam Taylor/Warner Bros.

Kissing Partners

A fight between Sheldon and Penny leaves Amy caught in the middle, while Howard (Simon Helberg, left) and Raj (Kunal Nayyar, right) try to help Leonard (Johnny Galecki, center) spice up his long-distance relationship with Priya, on THE BIG BANG THEORY. Photo: Adam Taylor/Warner Bros.

Amy and Sheldon

A fight between Sheldon (Jim Parsons, right) and Penny leaves Amy (Mayim Bialik, left) caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya, on THE BIG BANG THEORY. Photo: Adam Taylor/Warner Bros.

Bonding Time

A fight between Sheldon (Jim Parsons, left) and Penny (Kaley Cuoco, right) leaves Amy caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya, on THE BIG BANG THEORY. Photo: Adam Taylor/Warner Bros

Trouble Makers

fight between Sheldon (Jim Parsons) and Penny leaves Amy caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya, on THE BIG BANG THEORY. Photo: Adam Taylor/Warner Bros.

Long Distance Romance

A fight between Sheldon (Jim Parsons, left) and Penny leaves Amy caught in the middle, while Leonard (Johnny Galecki, right) tries to spice up his long-distance relationship with Priya, on THE BIG BANG THEORY. Photo: Adam Taylor/Warner Bros.