In Back to the Future (1985), Marty McFly watches The Man from Space (1955) with his future mother Lorraine Baines and her family on November 5, 1955, describing it as a classic. In reality, The Sleepwalker aired on November 5, 1955 while The Man From Space aired on December 31, 1955.
The original script for this show had Ralph taking the sleepwalking Norton along on a business trip. But since Jackie Gleason was always reluctant to do shows away from the Kramden's apartment building, the business trip was written out of the story. Nonetheless, the original concept for the episode somehow made it into being a TV Guide summary for syndicated reruns of the show in the 1970's (and possibly earlier, perhaps the first run summary contained this mistake and stuck). TVGuide summery read " Ralph's business trip is anything but restful, what with sleepwalker Norton taking his nightly strolls"