The boys run into problems when they file for a patent on The Big Bang Theory. "The Application Deterioration" is the 18th episode of the show's ninth season.
Koothrappali sells out Leonard and Wolowitz after they lie to their wives. "The Solder Excursion Diversion" is the 19th episode of the show's ninth season.
A heated argument breaks out during a get-together on The Big Bang Theory. "The Viewing Party Combustion" is the 21st episode of the show's ninth season.
Penny struggles to make a connection with Leonard's mother on The Big Bang Theory. "The Line Substitution Solution" is the 23rd episode of the show's ninth season.
Sheldon and Leonard's paretns have an awkward family visit on The Big Bang Theory. "The Convergence Convergence" is the 24th episode of the show's ninth season.
We've seen what it was like to put Leonard's mother and Sheldon's mother in a room together, but what happens when you also add Leonard's dad to that mix? That's gotta be an awkward dinner conversation.
Sheldon's mother (Laurie Metcalf) also visits for the special occasion, as Penny tries to plan a wedding ceremony that will include all of their family and friends.
Sheldon: I'll have a diet Coke. Penny: Can you please order a cocktail? I need to practice mixing drinks. Sheldon: Fine... I'll have a virgin Cuba Libre. Penny: That's... rum and Coke without the rum. Sheldon: Yes, and would you make it diet?
