"Felix" (Jack Lemmon) and "Oscar" (Walter Matthau) are best pals who get together once a week with their friends to play poker and shoot the breeze. Their friendship is about to be severely tested, though, when the former man announced that he has split up with his wife. "Oscar" rides to the rescue with an offer for him to move in with him, and what now ensues are a cleverly written, and generally entertaining, series of domestic scenarios in which these two men must learn to cohabit. It's pretty clear from the outset that "Oscar" is not exactly house-proud and as the story develops their…