Asobi Asobase -workshop of fun- OVA

Olivia is a blonde-haired beauty who was born and raised in Japan, but can’t speak any English. Despite always acting serious and as an intellectual, Kasumi is a bespectacled girl with short hair, who also can’t speak English. Finally, there’s the pig-tailed Hanako, who’s cheerful but can’t seem to become a normie. The three middle schoolers end up making a “Players’ Club”?! The ultimately cute, ultimately fun and hilarious teenage girls’ comedy is about to begin! (Source: Crunchyroll)

OVA episode bundled with fifth volume of manga.

The OVA features six separate stories revolving around the cast, some of which border on the bizarre; one of which is an MMORPG environment being played by Konata, Kagami, Tsukasa, and Nanako Kuroi, and another in which Kagami has a "suggestive" dream about Konata.

Once upon a time, five girls made an animated film and it was so much fun that they pledged to get jobs in animation so that someday they could make another film together. Now, two years later, Aoi, Shizuka, Ema, Misa and Midori have learned the truth about the anime industry: it's not always fun, it's anything but easy, and having talent isn't always enough to open the right doors. Which is why Aoi's overwhelmed by her job as a production assistant, Shizuka's waiting on tables between auditions, Midori's currently scriptless, Misa's switched to C.G., and Ema's working long hours as a key animator. Is it what they imagined? No. But are they ready to give up? Not just yet! Sometimes, when things happen in animation, they can happen in the most wonderful ways! (Source: Sent

OVAs of Seitokai Yakuindomo* which were either bundled with the limited editions of the manga volumes or as standalone OVAs.

A continuation of Zoku Sayonara Zetsubou Sensei, with more stories revolving around Nozomu Itoshiki, the extremely pessimistic or despairing teacher, and the students of class the 2-H, who are each hilariously abnormal in their own unique way except for the one relatively normal girl who hates being called normal. (Source: Anime News Network)

Unaired episode 13 of Acchi Kocchi that was included in Vol.6.

First year high schooler Midori Asakusa loves anime so much, she insists that "concept is everything" in animation. Though she draws a variety of ideas in her sketchbook, she hasn't taken the first step to creating anime, insisting that she can't do it alone. The producer-type Sayaka Kanamori is the first to notice Asakusa's genius. Then, when it becomes clear that their classmate, charismatic fashion model Tsubame Mizusaki, really wants to be an animator, they create an animation club to realize the "ultimate world" that exists in their minds. (Source: Crunchyroll)