Comical sidestories from within the main series' timeline and featuring some new characters.

Collected in Volume 28 of the main series.

The hilarious misadventures of the "Sket Dan"; a couple of high schoolers who help out people as part of their club activity: Himeko, the hot-headed ex-delinquent with a soft spot for cute things and a taste for strange food; Switch, the brainy otaku who only talks via a computerized speech-application; and Bossun, the atypical leader of this looney bunch, with the amazing power to... concentrate very hard!

Sket Dance won the 55th annual Shogakukan Manga Award in 2009 for best shounen manga.

From MoonFlower Scans:

Mustuki Yoneya, a high schooler, feels insecure and jealous because her constant companion and best friend, Nishio Kyuteki is starting to pay attention to a beautiful upperclassman. Seeing the senpai's attractiveness as a threat to her wish to remain at her best friend's side forever, she tries out several attempts as she strives to become the main object of Kyuteki's attention.

Note: Original language image is not available.

This could be any girl. Imagine being a heroine of a love story. Hatori also believed that one day she would get married to her childhood friend, Rita.

But that's not how the world works! This is a hilarious comedy that honestly paints a painful unrequited love story of this young girl!

1-4) Ai ga Love Shite You nanosa
Oono is unable to properly do his uniform check job because his adoration of Takeuchi distracts him, and Takeuchi mistakes this for Oono hating him and is sad at the idea of being disliked by the model student. Thus, Takeuchi is relieved and willing to reciprocate when he finds out that it isn’t hate but instead love that makes Oono so very awkward around Takeuchi.
from hazukashiikedo

5) Shiritsu Koukou Hetarebu

6) Nare Somehen

From Viz:
Mimori Kosaka's dream comes true when she's accepted to the Meidai Attached High School and gets to wear their super-fashionable uniform! She's excited about having a fun freshman year of high school, but things don't turn out as effortlessly as she had hoped.

Includes the following side stories:
Volume 1: Basically Pure-Hearted
Volume 2: Kiss the Mike!

From today, Meguru Kinosaki is a freshman in highschool. But it's not only that she hasn't had a first love yet; she's in fact a clean girl who's never been in touch with any guy apart from her older brother Toshiya. With this pure Meguru, her classmate Yuuma falls in love at first sight. He starts a determined attack, but the over-protective big brother blocks his way! Now Meguru's days start to turn around between a big brother with a sister complex and a pushy boy...!?

Two boys, Mitsuhashi Takashi and Itou Shinji, meet each other at a salon. It turns out both boys are transferring to a new school and decide to take the opportunity to reinvent themselves. No longer will they be run of the mill high school students, they will become the biggest delinquents Japan has ever seen!

From Bliss:

While buying food at the supermarket, Sunao Morihara gets kidnapped by a strange man, Kuon Tachibana, who turns out to be incredibly rich! His motive? He wants Sunao to be his friend. However, before Sunao realizes, being Kuon's "friend" actually means becoming his wife!

From Shinnen:

The Hachiouji family hunts demons in the darkness. The heiress of the Hachiouji family, Takamichi, lost her older brother at a very young age. She isolates herself, but, one evening, two werewolf pups are given to her. After just a few years, they have grown quickly, and they even go to the same senior high school that she does!

The main character Totoki is an ordinary high-school student who leads a mundane school life.
One day, a mysterious, primitive girl, Cherry appears before Totoki! Whatever Cherry does is a mammoth class! Because of that, Totoki is being thrown around mercilessly! Is Totoki's normal life gradually changing?!

Every day is boring, too boring...
Until a witch casts her spell on it?
Masa, a second-year student at a third-rate art school, draws because he doesn't know what else to do with his life.
Then he meets Aoi, an attractive first-year girl, who seems, somehow, like she might be a witch.
Will Aoi and her secrets light the fire in the gloomy Masa's heart?
Though it doesn't seem much like living, life goes on, as young men yearn only for yearning.
Though every day seems so inconsequential, the special spark of that time of life defines what it means to be young.

Her parents are getting divorced, so Mikuriya Natsumi has to transfer to a boarding school in the countryside and live in the dorms until she graduates from elementary school. Meanwhile, her mother's in the US arbitrating with her soon-to-be-ex husband.

Natsumi is at first cold and rude to her dorm-mates and prefers to keep herself from associating with them too much, but as she learns about each of the other kids' complicated circumstances and gets into all kinds of scrapes with them, she warms up to the place bit by bit. Of course, the dorm manager and her uncle, Mikuriya Takurou, being an excellent cook and all-round stolid presence helps! Still, cohabitation's tough...

After the ninja abolition act was passed in Japan, ninjas were forced to relocate. How will 15 year-old Shinoko handle transferring to an American high school, when she can barely speak English and is still a ninja in training!?

Kei has a secret crush on Yuzuyu, the most popular girl in the classroom. One day, he is attacked by unknown warriors and the one who rescues him is Yuzuyu herself, dressed in a weird costume, claiming that she is his property and that he can do with her as he pleases from now on.

Nono Nekomiya, Makoto Yuki, Iori Yuzuki and Matsuri Amachi all used to attend the same school. As close friends they spent their days in peace together as part of the light music club. One day, the school they attended closed down. All students had to transfer, making the four friends end up at different schools. Before they left, they placed a time capsule under a tree at their old school, promising to meet again, with Matsuri running off in bitter anger. Upon returning on the promised date, 3 years later with no contact in between, they find their time capsule has been dug up and turned into a lost and found game by an old teacher of theirs. While following clues left by the teacher, the four begin to remember past memories of life at the school as well as old feelings they may still have for each other.

Matsuri is a girl like all the other high school girls. She likes boys, especially one called Wataru, but he hardly notices her even though she watches him like a crazy gal. "Tough girls aren't my type," he once said, and now even three street guys call her a tough chick?! Nothing too good to say to the wrestling Princess. Being this kind of princess is nothing to be proud of for Matsuri so it's a secret that she keeps from her school mates, because it's her father who wants to make her a wrestler...but what will happen when she's discovered fighting those three guys by Arata, the bad boy who can even "fight cows"? Discover it and keep track of Matsuri Special!

Saitou, a rather arrogant kid, announces his super power to his class on the first day of high school. He imagines that it will make all the girls swoon, and he'll be crazily popular. Unfortunately, his ability to bend a spoon looks more like a cheap trick than a super power, and everyone laughs in his face.

Soon he learns that he is not the only kid with superpowers at the school, and there is even a Super Powers Research Club. He soon finds himself dragged into the society of a friendly invincible girl, a violent telekinetic girl, and a mind-reader. Rather than being swooned over, Saitou appears to have the least impressive ability of the group! Is there any way for him to get the happy high school life he was hoping for?

Otonashi-san has just transferred into a perfectly ordinary high school.
Silent and impassive, she's actually a kunoichi, a female ninja! (Not that she hides it well...)
See what a ninja, the famous traditional Japanese hero, would be like as a high school girl in this off-beat, four-panel manga!
Don't miss Otonashi-san's quirky appeal!!

A calm, quiet life at a new school is just what Aria needed. Unfortunately, it's not what she got! Chosen as Student Council President on her first day, Aria's attempts to just fit in are ruined by her nosy new classmates. Since she can't beat the use of her mocking former nickname, "The Lovemaster" she decides to go with it and turn the Student Council into a dating service! That's great for the school, but will Aria ever solve her own love troubles?