When Courteney Cox wore her fat suit for the first time in this episode, Matthew Perry walked by her without knowing who she was.
Considered by many critics and fans to be the best episode of the series.
During the prom video everyone notices that Rachel's nose was different in high school, and she says that she had an operation for a deviated septum. Some time after this Jennifer Aniston would herself get a nose job, which she publicly explained was because she too had a deviated septum.
When Chandler goes over to the woman who was checking him out she almost falls off of her chair while laughing but then catches herself.