The Addams Family Goes to School - S1-E1
Visible crew/equipment: When the phone rings and Thing hands it over to Morticia, the camera zooms out and you can the actor playing Thing quickly hide behind the couch. (00:24:15)
The Great Treasure Hunt - S2-E19
Visible crew/equipment: When Morticia bounces the anchor on the floor, the wire used to make it bounce is visible when she puts it down.
Christmas with the Addams Family - S2-E15
Continuity mistake: When the second Santa (Grandma) knocks at the children's door, in one brief shot Wednesday already has 2 dolls in her arms.
Morticia, the Breadwinner - S1-E26
Continuity mistake: As Pugsley tells Wednesday about satisfied customers, his arms are by his sides, then suddenly crossed.
Continuity mistake: As Fester talks with Gomez, he puts the fork with hamburger on it down in the bowl he's holding, and his right hand under the bowl. A second later, he's suddenly holding the fork.
Other mistake: As Kitty comes down the stairs, Hilliard screams, and Kitty goes back up. It's obvious the film was run backwards.
Answer: Basically from what I understand, they stuck the innards of a small flashlight into the base of the bulb and put a little switch on it. When he put it in his mouth and bit down, his teeth would hit the switch, which would turn on the flashlight and made the bulb light up.
TedStixon