Baker's Dozen

When a bonus episode is included with the DVD release of a series, beyond a simple Omake.

With many recent anime series being Twelve-Episode Anime, creators will sometimes add an entirely new 13th episode which may or may not fall into any strict continuity with the rest of the series -- in effect, an intentional Missing Episode.

Timing these after true finale episodes can seem awkward, even more so when they use the non-broadcasted aspect to up the Fan Service noticeably.

If the 13th episode is part of the original showing instead of a bonus, the group is called a Cour (french for 'a run').

Examples:

Anime and Manga

 * The DVD release of Parallel Trouble Adventure Dual has an extra episode tacked onto the end that partially undoes some of the events of the show's Grand Finale.
 * The final three episodes of DNA 2 never actually aired on television; they have only been part of the full continuity since the original video release.
 * Although it wasn't a Twelve-Episode Anime, the final episode of Excel Saga (Episode 26: "Going Too Far!") was submitted to air on TV. True to the parody nature of the preceding 25 episodes, #26 was a parody of gimmicky, shock-value final episodes; in addition to content that could have never aired in its timeslot, the episode also runs exactly one minute longer than normal. It was added to the Japanese and overseas DVD releases because it'd never get past the censors (which was the whole point).
 * The Uta Kata non-television episode gave some added conclusion to the end of the series, though it was still unfulfilling in some respects.
 * Please Teacher's bonus episode references two characters' "new" physical relation, despite previous implication.
 * The .hack//Sign platinum edition DVDs included additional episodes, including Recap Episodes, a skit that isn't Canon, an episode about Mimiru's past, and a Crossover episode entitled "Unison" that takes place after the video games, where both anime and video game characters meet.
 * When .Hack aired in Canada, these were shown on television after the regular storyline concluded.
 * Galaxy Angel used them, causing a bit of confusion in season one because the previous episode had the Angels state that it was the last.
 * Kashimashi: Girl Meets Girl - Bonus episode that completely turned the tables on the conclusion of the twelfth episode.
 * Although it is foreshadowed in the ending credits of episode 12.
 * Otome wa Boku ni Koishiteru features a 13th episode in which the now-chibified cast act out the play 'Tsunderella'.
 * The DVD edition of Elfen Lied features a 14th episode.
 * Higurashi came with Nekogoroshi-hen (Cat Killing Chapter), a single episode scenario based on a light novel.
 * Though it is a manga, rather than an anime, Pretty Face took this to extremes in its final bonus issue. The dramatic climax had come and gone, and even though this opened up one previously absent (but vital) character to the possibility of epilogue development, it still managed to locate the epilogue at a Hot Spring. This was used to display nude females in unprecedented numbers, whereas previously there had been very little uncensored nudity (despite plenty of other types of semi-harmless Fan Service).
 * Kamichu! has four bonus episodes. Yes.
 * Sola was already thirteen episodes, but it still got two bonus episodes. Only one was fanservicey. The other was set before the first episode of the broadcast.
 * Baccano is another thirteen episode series. It got three DVD-only episodes that, due to the nature of the series, retroactively fit into the story.
 * The Cowboy Bebop movie could be considered to be a two-hour long bonus episode, as it takes place within the continuity of the series despite being made after the series had ended.
 * Nanaka 6/17 has a bonus episode that doubles as a Day in The Limelight, as it focuses almost entirely on secondary character Amemiya rather than either of the main characters.
 * The fourteenth episode of Hidamari Sketch X365 is a DVD-only release.
 * Not a Twelve-Episode Anime example, but the first season of Clannad gave us Tomoyo's OVA, her route in animated form.
 * ~After Story~ gave us Kyou's OVA.
 * Spice and Wolf had the 7th episode as a DVD-only release, which explains where Holo got her second outfit seen throughout the rest of the series.
 * K-On!! gave us Episode 14 in the final Blu-ray. It followed the girls New Year's Eve, but with an new twist not in the manga; They performed at a local Live Show. After all that was done, the episode shifted back to following the Manga at the end.
 * Sora no Woto has two episodes exclusive to the DVDs. One of them involves the underage cast being Unsuspectingly Soused.
 * Angel Beats! will have additional episode included in 7th Blu-ray release.
 * Durarara gets two extra chapters available only on DVD. One of them is episode 12.5, which features a wacky mix of red bags (and Mikado's group in a pretty ridiculous situation); while chapter 25 includes a full battle between Izaya and Shizuo. (Mikado and Anri end up in a pretty awkward situation, and Celty is chased once again by the cops.)
 * THE iDOLM@STER - The Live For You OVA came bundled with the Live For You version of the game.

Live Action Television

 * The DVD of Firefly included 3 episodes that were not aired, making the grand total 14.
 * The first season of Dollhouse was originally signed to thirteen episodes for the broadcast run as well as the DVD set. However, this included the pilot episode, which Fox decided was too confusing and didn't get into the action quickly enough, and so they didn't run it. Therefore, the episode count for the broadcast run was reduced to 12. However, delivering just twelve episodes would violate the contract they had with the company putting out the DVDs, so a stand-alone thirteenth episode was created strictly for the DVD. As a result, the DVD set will have fourteen episodes: the twelve episodes broadcast, the stand-alone thirteenth, and the original unaired pilot.
 * Both the Freaks and Geeks and Undeclared DVD sets contained unaired episodes.

Western Animation

 * Western example: The makers of Tom Goes to the Mayor consider the 30th episode to be like a bonus episode, as both episode 29, which ends with Tom curled into the fetal position on the Mayor's floor, and episode 30, which ends with Tom and the Mayor soaring off into the skies on a motor scooter, are both fitting ends to the series in their own way.
 * Teen Titans put a "lost episode" as an extra for the DVD movie. It explained a secondary season 5 villain and was half as long as a normal episode so they couldn't put it on the air.
 * This episode was also available earlier online, if you had a special code from a cereal box.
 * The sole season of the animated cult series Downtown was eventually released on a two-disc set by the creators. The DVD included the "bonus" Halloween episode, which never got aired during the original run - but was shown in various non-US countries when it ran in syndication.
 * The complete set of Dr. Katz, Professional Therapist gives us three episodes that were unaired in the U.S.
 * Homestar Runner frequently does this in their DVD's.