The overnight Saturday Night Live rerun that airs tomorrow morning is the one from 2/10/79 hosted by Cicely Tyson with musical guests Talking Heads. It's not, as I recall, a very memorable episode.
This coming week on GSN's What's My Line? reruns: Tomorrow morning's Mystery Guest is Gene Kelly. Monday morning, it's Sal Mineo. Tuesday morn, catch Buddy Hackett. Wednesday, we get Tony Franciosa and Shelley Winters, plus one of the non-celeb guests is the great glamour photographer, Bunny Yeager. Thursday AM, you have your Julius LaRosa and then on Friday, it's Robert Sterling and Anne Jeffreys. These episodes are from June and July of '57.