Richard tells the story of his jacket being stolen while his sister watched. The sister is not given a name and is never mentioned again, not even in any of the episodes where Richard's parents appear.
Caroline: (about Del) You could try being nicer to him.
Richard: Yeah, and I could watch Tori Spelling play Medea. But life is too short.
(Caroline and Del are kissing on the sofa)
Richard: I see you've moved on from the kitchen table.
When Annie asks about Richard's mugger he exclaims that he was mugged by a member of the Lollipop Guild.
The Lollipop Guild was one of the groups of little people met by Dorothy when she arrives in Oz in the movie The Wizard of Oz (1939).
When Del hands Caroline his Blockbuster card Caroline asks if he thinks he's going to go nuts and rent "Howard the Duck", to which Del replies that the movie was underrated.
Howard the Duck is a movie made in 1986 starring Lea Thompson, who plays Caroline, and Tim Robbins. It's about another planet where ducks rules the world rather than humans and Howard is transported to Earth. It was made by George Lucas who was already in debt and replying on a hit to stay in the black. The movie bombed leading Lucas to sell of many assets and is generally thought of as one of the worst movies ever made.