Continuity mistake: When Pam is in the office talking to Cliff and he tells her about the curfew time, she has a pencil in her hand and a pad in her lap. In the next shot, Cliff offers her a pencil and tells her to take the pad (which is on his desk).
Theo and the Kids (2) - S7-E26
Other mistake: After the commercial, when Olivia and her friend are watching TV, they look at each other and laugh, obviously on cue. They weren't even looking at the TV and started laughing at exactly the same time.
You Can Go Home Again - S7-E10
Other mistake: When Denise hangs up the phone after inquiring about the two bedroom apartment, actress Lisa Bonet's multiple tattoos are visible on the back of her neck and shoulder. In every other scene her tattoos are obscured with makeup as they wouldn't fit with Denise.
Continuity mistake: When Jake is describing the accident, he takes some glue tubs from the counter. Partway through the scene they change to glue bottles.
Continuity mistake: When Theo and his parents are talking in the kitchen, there is a box on the table. The cover is on and Theo is standing in front of the table, the next shot he is standing next to the table leaning on a box and the cover is off.
Continuity mistake: When Theo walks into the kitchen, there are two half gallons of chocolate milk on the stove. When he sees the milk and picks it up there is only one. Theo places it on the table, later the second one reappears on the stove, before he leaves Clair gives him the one that is sitting on the stove, and the one on the table disappears.
Continuity mistake: Theo walks into the living room eating a banana and holding an apple - he eats the banana throughout the scene. At one point he starts eating the apple, the banana peel disappears, and a mandarin orange appears on the couch next to him.
Character mistake: Rudy says that the last time some of Anna and Russell's friends visited them was during their 50th anniversary, and she got rich because they gave her money. In the actual episode of the Golden Anniversary however, the only guests at Anna and Russell's dinner party were the immediate family and Elvin.
Chosen answer: That is the song "Open the Door Richard."