The 100th episode of the series.
When Richie introduces Potsie at the dance at the beginning of the episode, he introduces him as "The Velvet Cloud", an obvious reference to Mel Torme who was nicknamed "The Velvet Fog".
Audrey Landers was in this episode and the previous episode had her sister Judy Landers
This is the second time that Don Most (Ralph) and Audrey Landers (Kitty) worked together. They also appeared as a young couple involved in a car accident on Emergency! (3:14, "Computer Error") shortly before Happy Days first aired.