Leonard can only bring one guest on a trip to see CERN's Large Hadron Collider (the world's largest and highest energy particle accelerator) in Switzerland on Valentine's Day.
Comedy
More episodes from Season 3
More details
Directors
Mark Cendrowski, Peter Chakos, Anthony Rich
Cast
Johnny Galecki, Jim Parsons, Kaley Cuoco, Simon Helberg, Kunal Nayyar, Sara Gilbert