"The Switch" is the 97th episode of NBC sitcom Seinfeld. This was the 11th episode for the 6th season. It aired on January 5, 1995. This episode is notable for revealing Kramer's first name as Cosmo.
After playing tennis Elaine is recognized by Mrs. Landis, a former potential employer from Doubleday. Elaine lends Mr. Pitt's tennis racket, a Bruline, to her in hopes of getting a new job. Meanwhile, Jerry is dating Sandy, a "non-laugher". George is dating Nina, a model who eats a lot and who Kramer thinks may be bulimic.
George has dinner with Nina; she feasts on the food and then goes to the bathroom to "freshen" herself. Jerry has dinner with Sandy; he keeps making funny remarks but she doesn't laugh, she just says "that's funny".
Back at the apartment, Jerry mentions how the jokes just bounce off his girlfriend. Mrs. Landis got hurt playing tennis and Elaine hasn't yet picked up the racket. George is now certain his girlfriend is bulimic because he heard a "blah" in the bathroom.
George wants a matron to spy on Nina to verify if she intentionally throws up. Kramer's mother, Babs, happens to be a matron, but Kramer doesn't want anything to do with her.
Mrs. Landis is very sad and, because of her injury, she may never play tennis again. Elaine doesn't have the heart to ask for the racket back. George and Kramer go the restroom, and Babs Kramer reveals her son's first name: Cosmo. Back at the apartment, Elaine says Mr. Pitt needs his racket in a match against Ethel Kennedy. George comes with the news of Kramer's name, and everybody laughs. Cosmo Kramer accepts his name and says he was running from his true self.
When Jerry goes to his girlfriend's apartment he meets Laura, Sandy's roommate, who does laugh at his jokes. Later, he talks with George, saying he intends to try the "switch". George declares it's impossible: no one in western history has ever switched a girlfriend for her roommate. Jerry and George spend long hours devis...