"The Letter" - Season 3 Episode 21 of Seinfeld First Airs
"The Letter" is the thirty-ninth episode of the sitcom Seinfeld.
The episode was the 21st of the third season. It aired on March 25, 1992.
Kramer poses for a portrait by Jerry's girlfriend, Nina (Catherine Keener), which an elderly couple admires. George feels obligated to buy something when he accompanies Jerry to his new girlfriend's art studio, and purchases a $500 painting, which he tries to sell to Jerry for $10 shortly thereafter.
Elaine wears a Baltimore Orioles baseball cap in the owner's box at Yankee Stadium, and refuses to remove it. Jerry finds out his new girlfriend is a plagiarist after he hears the words she wrote in a letter on television (specifically, the Neil Simon film Chapter Two). Just before confronting Nina about the note, two of Nina's customers walk in and buy Kramer's portrait.
Elaine gets a chance to return to Yankee Stadium with her boss and is told to wear the Baltimore Orioles cap. This, after already having come up with an excuse to miss her boss's nephew's bris, so she could attend the prior game. She claimed that her father was ill at home in Baltimore, and her presence was required. The elderly couple buy "The Kramer" for $5,000 and invite Kramer over to their house for dinner.