Homer once again shows his talents as a musician (he use to be a part of the BeSharps).
Lurleen Lumpkin can be seen standing in the mall audience. Like Lisa, her musical career was also managed by Homer.
Homer also yells kind words while outraged in Postcards From the Wedge.
Lisa is the only one of the family who did not get food poisoning from the vegetables she ate. In "Grade School Confidential", her vegetarianism also saved her from food poisoning. However, she pretended she caught it just because she wanted to leave the party without being rude.
Lisa's relationship with Ralph Wiggum is brought up in this episode where he sang the ABC song incorrectly. After he is finished Lisa says "I can't believe I used to date him."
When we see Carl in the audience from behind, he has yellow skin.
Lisa singing about her cat that she lost at Christmas eve is from the episode, Simpsons Roasting on an Open Fire.