"We eat here every Friday because Norma's is Oak Cliff," said businessman and community activist Ralph Isenberg. Norma's is that and much more. It's an archetypal Southern breakfast and lunch spot, a place that feels familiar from the first visit, and, best of all, it's a living time capsule of a long-gone Dallas. Opened in 1956, Norma's has defied modernization. As a result, the effect is that of having ventured into one of the black-and-white photographs that crowd the walls. As you wander around the two spacious rooms you see neither the crumbling Texas Theater of today nor the already seedy hideout for Lee Harvey Oswald, but a glamorous and spiffy movie basilica with Gable and Harlow on the marquee. The staff provides a similar window on the easy, unstudied friendliness of an earlier Dallas.