Aired Thursday June 13, 1:30pm - 2:00pmon E4

The Big Bang Theory

Series 3 Episode 15: The Large Hadron Collision

Leonard is invited to Switzerland on Valentine's Day to see the world's largest particle accelerator. Sheldon is gutted when Leonard asks Penny to go with him, as a Valentine's Day treat, instead of him. Sheldon tries to coerce the couple into letting him take Penny's place, will they relent?

Holiday / Sitcom
Original air date
Cast and crew
  • Mark CendrowskiDirector
  • Johnny GaleckiLeonard
  • Jim ParsonsSheldon
  • Kaley CuocoPenny
  • Simon HelbergWolowitz
  • Kunal NayyarKoothrappali