TV's most iconic 100th episodes

“Sweet Seymour Skinner’s Baadasssss Song” – Season 5, Episode 19 (28 April 1994)

Cast your mind back to 1994. The Simpsons was still at its peak and it wasn’t about to do something so obvious as a 100th episode special. It simply carried on doing hilarious business as usual with this story about Springfield school principal Seymour Skinner getting fired, and only referred to its 100-ness with the chalkboard gag announcing: “I will not celebrate meaningless milestones”. Of course, they did do a big celebration almost two years later for, er, the 138th episode…

“The Gift” – Season 5, Episode 22 (22 May, 2001)

It might not be the best Buffy (that award has to go to the musical “Once More, With Feeling”), but no other 100th episode has celebrated the milestone with such whopping dramatic impact. Writer/director Joss Whedon goes the whole hog for the season 5 finale, bringing the battle against hell-god Glory to a frenzied climax that ends with Buffy sacrificing herself to close an inter-dimensional portal. And how’s this for a bow-out grace note? On the vampire slayer’s gravestone we read the epitaph: “She saved the world. A lot”.

“100” – Season 5, Episode 20/21 (21 April, 2011)

Having her sitcom set in a TV studio that produces a Saturday Night Live-style show proved a gift for Tina Fey when 30 Rock hit 100. So we got this gag-stuffed two-parter set around The Girlie Show’s own 100th episode, in which Fey’s Liz Lemon has to save “TGS” from cancellation – while a gas leak causes hallucinations among the crew, with guest star Michael Keaton warning of the following possible side effects: “revelations of secrets, telling truths, flashbacks, headaches, nostalgia…” all great ingredients for a classic 100th episode. Except the headaches.

“Good Luck, Ruth Johnson” – Season 5, Episode 9 (10 December, 1998)

Different shows find different ways to work their “100th birthday” into the narrative, and classic hospital drama ER achieved this by setting the ninth episode of its fifth season during the centenary of County General Hospital. As other story strands play out, young Dr Carter (Falling Skies' Noah Wyle) is charged with giving a 100-year-old woman a tour of the hospital – where she was born on the very day it opened. Their conversation shows how heyday ER was as strong during its quieter moments as it was in its bigger, bloodier scenes.

“Cancelled” / “A Little Bit Country” – Season 7, Episodes 1 & 4 (19 March & 9 April, 2003)

This entry’s a two-for-one, but we’ll allow it for South Park. “Cancelled” was originally intended as the profane ‘toon’s 100th episode, but a scheduling rejig meant it ended up as the 97th. In truth, it feels more like a 100th than the true 100th “A Little Bit Country”, riffing as it does on the show's first-ever episode and making jokes about TV series declining in quality after hitting 100. Still, Iraq invasion satire “A Little Bit Country” ends its debate about war with: “Who cares? 100 episodes!”.

“Redemption Part I” – Season 4, Episode 26 (17 June 1991). Find it on Netflix

Star Trek: The Next Generation always liked to save its biggest plot revelations for its season finales. And it delivered a photon-torpedo-strength shock at the end of its 100th episode, which saw out Season 4. If it wasn’t enough that the crew of the USS Enterprise had become embroiled in a burgeoning Klingon Civil War, “Redemption Part I” finished with Picard (Patrick Stewart) meeting a new foe: Romulan officer Sela, the spitting image of dead-since-season 1 security chief Tasha Yar. An OMG moment before that phrase even existed…

“The 1,000th Show” – Season 5, Episode 5 (11 November, 1997)

Having tried to overmodestly downplay the upcoming 1,000th broadcast of his radio show, celebrity shrink Frasier Crane (Kelsey Grammar) ends up with a huge celebration at the Seattle Space Needle. But will he ever get there? A series of comical mishaps means he and his prim brother Niles (David Hyde Pierce) get waylaid in the city’s streets. It’s Frasier at its best: showing how small bad decisions can snowball in the funniest way.

“The One Hundredth” – Season 5, Episode 3 (8 October, 1998)

Aka “The One With The Triplets”. Having come up with a surrogacy plotline for Phoebe (to account for actor Lisa Kudrow’s own pregnancy), this milestone episode brought that arc to a big conclusion. It moved the action entirely away from all the usual Friends sets and into a hospital, where Rachel (Jennifer Aniston) and Monica (Courteney Cox) also flirt with male nurses (ER's George Clooney and Noah Wyle) and Joey "gives birth" to kidney stones in an adjoining room.

“My Way Home” – Season 5, Episode 7 (24 January, 2006)

The Zach Braff-fronted hospital comedy played a really smart card with its 100th, basing its “JD just wants to get home” plot entirely around The Wizard Of Oz, filling the episode with references and homages to the classic 1939 fantasy musical. Some are obvious – such as the heart transplant and the hospital floor’s yellow line (or “brick road”) – others are more subtle; like the opening song being “Africa” by… Toto.