The Irish Pub Formulation

When Raj's sister has a one-day layover he forbids the others from hooking up with her, unaware she and Leonard already did long ago.

TV-14-DL
Season 4 | Episode 6

Cast

Jim Parsons

as Sheldon Cooper

Johnny Galecki

as Leonard Hofstadter

Kaley Cuoco

as Penny

Simon Helberg

as Howard Wolowitz

Kunal Nayyar

as Raj Koothrappali