Tropes that apply to a particular single episode of a TV show.

Significant date episode

Episodes that revolve around what the characters do (or not) to celebrate culturally significant dates.

Genre shift episode

The show switches genres for one episode but keeps the main cast.

Unusual location episode

Episode where the main cast goes to places they don't usually hang out at.

Unusual situation episode

Episodes where the main cast is placed into unusual situation.

Illness episode

Episodes where members of the main cast fall ill or are injured.

Unusual activity episode

Episodes where members of the main cast engage in unusual (for them) activities.

Contest/sports/game episode

Episodes where the main cast participates in sports or other kinds of games and contests.

Character-centered episode

Episodes focusing on secondary characters, personality traits of the main cast, exotic creatures, or even inanimate objects.

(Non-)Continuity episode

Episodes important (or completely irrelevant) to the show's overall continuity.

Production trivia episode

Episodes notable for unusual format or production details.