Anthology episodes

Over the long run of the Simpsons there have been many episodes which feature 3 mini-stories that are held together by a backbone story plot. The reason for 3 mini-stories is due to the commercial break structure of the show.

Treehouse of Horror episodes
The Treehouse of Horror episodes are the most well known but there have been many others. They began in season 2 and each season since has had one Treehouse of Horror episode. After season 5, the backbone story was removed from the Halloween episodes but the 3 mini-stories still remain.

Episodes

 * Treehouse of Horror from season 2
 * Treehouse of Horror II from season 3
 * Treehouse of Horror III from season 4
 * Treehouse of Horror IV from season 5
 * Treehouse of Horror V from season 6
 * Treehouse of Horror VI from season 7
 * Treehouse of Horror VII from season 8
 * Treehouse of Horror VIII from season 9
 * Treehouse of Horror IX from season 10
 * Treehouse of Horror X from season 11
 * Treehouse of Horror XI from season 12
 * Treehouse of Horror XII from season 13
 * Treehouse of Horror XIII from season 14
 * Treehouse of Horror XIV from season 15
 * Treehouse of Horror XV from season 16
 * Treehouse of Horror XVI from season 17
 * Treehouse of Horror XVII from season 18
 * Treehouse of Horror XVIII from season 19
 * Treehouse of Horror XIX from season 20
 * Treehouse of Horror XX from season 21
 * Treehouse of Horror XXI from season 22
 * Treehouse of Horror XXII from season 23
 * Treehouse of Horror XXIII from season 24
 * Treehouse of Horror XXIV from season 25
 * Treehouse of Horror XXV from season 26
 * Treehouse of Horror XXVI from season 27
 * Treehouse of Horror XXVII from season 28
 * Treehouse of Horror XXVIII from season 29
 * Treehouse of Horror XXIX from season 30
 * Treehouse of Horror XXX from season 31

Non-Traditional episodes
Several episodes do not fall into the normal pattern of 3 mini-stories.

Vignettes
In 22 Short Films About Springfield Bart and Milhouse wonder about the various stories happening around Springfield. The episode inspired Simpsons creator Matt Groening to come up with a concept of a possible spin-off series called Tales from Springfield, about the recurring characters of Springfield, but the series was never picked up.

In Springfield Up flashbacks of several characters are used featuring them at different points of their lives.

The episodes Another Simpsons Clip Show and All Singing, All Dancing are more properly categorized as clip shows but also fit the pattern of a vignette anthology type story. The separate items are taken from previous episodes but the backbone story involved with these two plays into the overall clip content. In Another Simpsons Clip Show the backbone is love stories, All Singing, All Dancing has a musical theme.

The other clip show episodes could be considered anthology stories, however with So It's Come to This: A Simpsons Clip Show, The Simpsons 138th Episode Spectacular, Behind the Laughter and Gump Roast the central backbone story is not connected to the clip content which is much more random and general. Considering the Simpsons is more than 20 years old and still going strong with over 600 episodes the fact that there are only six clip shows is outstanding.

Over-lapping POV
In this format the same story line is told from several different perspectives. This story telling technique has been used by several other FOX shows including Malcolm in the Middle and Terminator: the Sarah Connor Chronicles.

In Trilogy of Error the story is told from Homer's POV then Lisa's, then finally Bart's.

The Seemingly Never-Ending Story is another POV story, with several different threads telling the same narative from different perspectives.

List of Episodes
What follows is a list of these episodes.

Season 2

 * Treehouse of Horror

Season 3

 * Treehouse of Horror II

Season 4

 * Treehouse of Horror III

Season 5

 * Treehouse of Horror IV

Season 6

 * Treehouse of Horror V
 * Another Simpsons Clip Show

Season 7

 * Treehouse of Horror VI
 * 22 Short Films About Springfield

Season 8

 * Treehouse of Horror VII
 * The Simpsons Spin-Off Showcase

Season 9

 * Treehouse of Horror VIII
 * All Singing, All Dancing

Season 10

 * Treehouse of Horror IX
 * Simpsons Bible Stories

Season 11

 * Treehouse of Horror X

Season 12

 * Treehouse of Horror XI
 * Trilogy of Error
 * Simpsons Tall Tales

Season 13

 * Treehouse of Horror XII
 * Tales from the Public Domain

Season 14

 * Treehouse of Horror XIII

Season 15

 * Treehouse of Horror XIV
 * Margical History Tour

Season 16

 * Treehouse of Horror XV

Season 17

 * Treehouse of Horror XVI
 * Simpsons Christmas Stories
 * The Seemingly Never-Ending Story
 * The Wettest Stories Ever Told

Season 18

 * Treehouse of Horror XVII
 * Revenge Is a Dish Best Served Three Times
 * Springfield Up

Season 19

 * Treehouse of Horror XVIII
 * Love, Springfieldian Style

Season 20

 * Treehouse of Horror XIX
 * Four Great Women and a Manicure

Season 21

 * Treehouse of Horror XX

Season 22

 * Treehouse of Horror XXI
 * The Fight Before Christmas

Season 23

 * Treehouse of Horror XXII

Season 24

 * Treehouse of Horror XXIII

Season 25

 * Treehouse of Horror XXIV

Season 26

 * Treehouse of Horror XXV

Season 27

 * Treehouse of Horror XXVI

Season 28

 * Treehouse of Horror XXVII

Season 29

 * Treehouse of Horror XXVIII

Season 30

 * My Way or the Highway to Heaven
 * Treehouse of Horror XXIX

Season 31

 * Treehouse of Horror XXX

Trivia

 * Up til season 20, each anthology episode consisted of 3 short stories. The episode "Four Great Women and a Manicure" however had 4 short stories.
 * Between the third story and forth story, Marge comments "well, 3 stories, the way we always have it".