Easter egg: Season 17 Region 2 DVD box set contains some hidden stuff including deleted scenes. They can be accessed by clicking on an episode which brings up the episode menu, then press the up arrow which may highlight a little square. Pressing left or right may select more squares.
The Simpsons (1989)
1 easter egg in show generally
Continuity mistake: When Homer's Vegas wife shows him the video in front of Marge, it shows Homer kissing Ned. This didn't happen when she showed it in the Vegas episode.
Homer's brain: It's simple, just use reverse psychology.
Homer: Reverse psychology? That sounds too complicated.
Homer's brain: Alright, don't use reverse psychology.
Homer: Alright, I will!
Trivia: The only voice artists who regularly perform as only one character are Yeardley Smith as Lisa and Marcia Wallace as Edna Krabappel. Yeardley has also voiced different versions of Lisa (Lisa Jr. and Lisabella) in at least two other episodes.
Question: Which episodes feature the "Howling Dog" (usually used on outside shots of buildings)?