One of the few episodes I ever watched of this show, and it just had to star my least favorite person ever: Hilary Duff. However she did play a wannabe quite well, being one herself if you ask me.
Joan is being taunted by the popular girls, and the character HD plays makes a snide remark about her school bag. Joan retorts (quite well, Joan deserves a standing ovation for this one) back "And your heads, from Mattel?" referring of course to the manufacturer of Barbies. And then Joan saves the girl's life from a coming car. At first the girl, Dylan (I think that was her name that Hilary Duff played but not completely certain) is so grateful and spills her secrets: her mom isn't a lawyer like she is telling the popular girls she hangs with, she works in an airplane restaurant. She also gives Joan a watch, which Joan wears grudgingly. I love Joan as a character, she is so sarcastic reluctant and yet you gotta love her.
Then later there are accusations against Joan, and Dylan doesn't fire them back like she should've. Dylan goes back to the popular girls and the snide remarks and Joan accuses her of making that sob-story about her mom up, leading Dylan to tears and her popular girl friends in disgust.
In the end Dylan is at the cafeteria, not knowing what to eat for dessert because she doesn't know what she likes because she's spent so much time copying other people. This is where Joan comes in, accompanying her and having her try all the desserts. Great episode.