Bart, Lisa, and Maggie are watching Itchy & Scratchy and Dad declares it too violent so they have to do something else. Bart then dismantles the TV and makes his own show called The Bart Simpson Show. He has a hand puppet named Ed (that looks like Binky from Life in Hell) who introduces the show. But When Bart starts talking about how he ran over his Dad's head with his bike, Dad comes back in telling the kids to stop watching violent TV, but is shocked to see that Bart's on TV. Dad then notices Bart took out all the parts to the TV and angrily heads towards him, so Bart shuts the curtain to get away but Dad beats him behind it. Maggie walks up to the TV and pulls open the curtain to see what's going on: Homer is strangling Bart, who then strangles Homer. As both Homer and Bart choke in pain, Maggie and Lisa then clap.
In the beginning of the episode at 0:10 in, Homer is standing in the doorway to the living room watching the kids, and behind him you can clearly see the visual effect commonly known as the hall of mirrors, in which an image is repeated between two mirrors giving the appearance of infinite doorways, except that it is only repeated behind him.