CBS has announced the details of the fifteenth episode of the season, "The Large Hadron Collision", which will air February 8th.
"The Large Hadron Collision" - 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, on THE BIG BANG THEORY, Monday, Feb. 8 (9:30-10:00 PM, ET/PT) on the CBS Television Network.
The Big Bang Theory