Deliberate mistake: In the scene where Alicia Silverstone and Dave Foley are in the porno store, they cut to a guy standing behind a counter. All of the explicit shots of the videotape covers on the countertop are blurred out.
Factual error: After some tinkering with a TV set and a mirror, Calvin Webber finds that he can watch a TV show in reverse image. On the screen is the opening of "The Honeymooners" showing the cast members' names superimposed on a picture of the moon, with Jackie Gleason's face. But the picture is in color, mostly blue and off-white, while the actual "Honeymooners" series was filmed in black-and-white.
Continuity mistake: When Calvin first goes back up to the surface, he encounters the bartender. The bartender is shown as himself moving at first then he freezes while Calvin's light is on him. Again it shows the bartender but you can tell if you look close enough he is just a piece of cardboard falling to the ground. Then Calvin tells the bartender to leave his elevator alone. (00:27:03)
Chosen answer: I think this is a reference to two things: home shopping networks (which often offer free inducements such as lawn furniture or steak knives to shoppers who "call now" or "act now"; it's also probably a reference to Calvin's age - elderly people liking lawn furniture.
Sierra1 ★
Years ago, there were TV commercials of used car salesman that would throw in lawn furniture or other desired household items when you buy a car from them. Pretty sure that is the reference here.