Continuity mistake: Cliff says "a young trumpet player while sitting in the bandstand watching the dancers". But in all the later episodes, Russell plays the trombone, and he had been for a long time.
Revealing mistake: When Robert grabs Scott's shirt, Scott hits the wall and it moves backwards about an inch showing that it's fake.
Factual error: When Clair and Denise are watching the Bears vs. the Giants game, they comment on how cute player number 16 is. In 1985, nobody wore 16 for either the Bears or the Giants. Former Bears' placekicker Bob Thomas wore it from 1975 to 1984 until he retired. 16 wasn't worn again by the Bears until Tim Lashar, another kicker, wore it in 1987. Also, 16 had long since been retired by the Giants. It was last worn by Frank Gifford.
Visible crew/equipment: Look closely when Clair gets up after saying to the kids "I'm glad we had this chat", you can see a tip of a camera on the right.
Continuity mistake: The amount of milk in Robert's glass changes a few times throughout the scene in the kitchen.
The Dentist - S2-E16
Continuity mistake: The amount of orange juice in Cliff's cup changes - you see him filling his cup, the next shot it is almost empty, a couple of shots later it is now full again.
Continuity mistake: When Theo puts the phone down, the handset cord is next to the phone. The next shot it is now under the phone, when the phone rings it is now next to the phone again.
Continuity mistake: In this episode, Rudy is riding her bike around the house which is right on the corner of a block. Since when is their house on the corner?
Continuity mistake: After Clair turns off the record, the folder on the table changes position.
Chosen answer: That is the song "Open the Door Richard."