[s2e17] The Terminator Decoupling -

Raj manages to talk to her after drinking what he thinks is beer, only to lose his "magic" when Howard reveals it is non-alcoholic.

While the boys are on the train, Sheldon realizes he left a flash drive with his research paper at the apartment. [S2E17] The Terminator Decoupling

In a highlight of the season, Penny loses patience with Sheldon’s complex instructions and simply smashes his puzzle box to get the drive. Raj manages to talk to her after drinking