Raj: What is so exciting?
Sheldon: It's a letter from Dr. Wolcott. We've been corresponding about my string theory research.
Leonard: Wait. Robert Wolcott? Like Wolcott's Theorem Wolcott?
Sheldon: The very same.
Raj: Didn't he go crazy and cut off all contact with people?
Howard: Yeah, he was driven mad by a friend who kept wanting to talk about the Hulk's car insurance!