Goofs

Sheldon cites his and Leonard's Roommate Agreement in claiming dibs on being Leonard's guest to visit the Large Hadron Collider and they both tell Penny there were no girlfriend clauses (because neither expected to have one move in with them) when she asks about it. However, in the earlier The Vartabedian Conundrum (2008), Sheldon cites a girlfriend clause (involving refrigerator shelf space) when Stephanie Barnett (Sara Rue) stays at the apartment.

Sheldon says that the Swiss dish of cholermüs is a traditional breakfast dish. Actually, it is typically eaten for supper.

When Leonard is trying to get Penny to guess where they will spend Valentine's Day, Penny guesses the Matterhorn at Disneyland. After Leonard asks how that will require air travel, she guesses the Matterhorn at Disney World. The Matterhorn is not an attraction at Disney World. However, it's quite possible that Penny simply doesn't know this and just assumes there is a Matterhorn attraction at both parks.

Sheldon tells Penny he has dreamed of visiting the LHC since he was 6, but in the Roommate Agreement the clause states the LHC is under construction. In actuality, Sheldon said he had been looking forward to seeing LHC since he was 9 years old, not 6. Also, the Large Hadron Collider got construction approval in 1995 (with actual construction taking place between 1998 and 2008), but it was in the planning stage long before that. In addition, LHC was built in the tunnels of, and replaced, the Large Electron-Positron Collider, which was built in 1983. It is entirely possible for Sheldon to have been aware of the Large Electron-Positron Collider and the plans to update it to the Large Hadron Collider when he was 9 years old (or even 6 years old) and is now using its current name.

After Leonard tells the gang about him going to Switzerland, Sheldon gets excited and says that he'll start packing. Given that he always asks someone to drive him, he couldn't possibly have gone home to pack.

Sheldon believes that he got the flu from Penny because he hugged her in the laundry room. But it takes several days for the flu virus to incubate in a person, so both of them would have gotten the virus from someone else days before that happened.