The Large Hadron Collision

Leonard faces a dilemma in choosing between Sheldon or Penny to accompany him to Switzerland to see CERN's Large Hadron Collider on Valentine's Day.

TV-14-DL
Season 3 | Episode 15

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