From Tokyopop:
Young Mikan runs away to Tokyo to follow her best friend, Hotaru, who has been enrolled in an exclusive, secretive private school for geniuses. But it turns out that Alice Academy is a lot more than meets the eye. If Mikan wants to stay by Hotaru's side, she has to both pass the strange "entrance exam" and face the even greater challenge of befriending her very odd new classmates. Whether it's Hotaru's gift for inventing gadgets, the cranky Natsume's fire-casting ability, or Professor Narumi's control of human pheromones, everyone at the school has some sort of special talent. But what ability, if any, does Mikan possess? Mikan is going to have to rely on her courage and spunk if she's going to stay in school, or even stay alive!

From Nigihana: One day a high school student named Haruhiko who is aiming for Tokyo University has discovered a very important secret. From the closet, appeared a beautiful girl with a black pony tail, Utsuki who came from "Moon Village" with her Ninja Troop said to him, "It's been 7 years, master."

From Nagareboshi Manga:
Sachi has always been known for her gorgeous amber-colored hair that she inherited from her mother. She has a happy enough life, except for the fact that her mother is dead, which she keeps a secret.
One day, she is approached by a classmate who seems to know all her family's secrets, and is forced into his "Money Game".

This year, the student council has decided to add an exciting new contribution to the school's culture festival; an Idol performance! However, they don't actually have the money to hire any real Idols, so someone's going to have to train up an idol group from their female classmates. Hirano Harufumi is that unlucky someone. He has no interest in Idols at all, but he must put together a performance or risk expulsion from the school for his failure.Not surprisingly, most high school girls are too embarrassed and self-conscious to dance and sing in front of their classmates in a skimpy outfit. When Harufumi tries to think about who he would like to see as an Idol, his thoughts are drawn to his cute, shy, clumsy childhood friend Aizawa Momoka. Will Harufumi be able to convince her to be an Idol before it's too late?Sequel:> Atashi no Idol ( http://mangapark.com/search?q=atashi-no-idol )

1) Love Making
Student Shinobu loves cafeteria food and usually cleans his plate, the only thing he won't eat are carrots. When school nutritionist Tatsuya catches him throwing out food, he has to think of a creative way for Shinobu to eat his vegetables...

2) The Pigheaded Deity
Keisuke's grandfather always warned him about the Tengu living on the mountain, but that was when he was a child. Keisuke's an adult now, so why is he seeing a handsome man with wings?

3) Let Me Drown in the Sea of Love!
Atsushi is a failing romance novelist whose active fantasy life has wrapped itself around fish shop employee, Sakurai. Can Atsushi wake up long enough to make a move?

4) God, Give Me a Wife
Kurachi Daisuke is a high school teacher with a problem: he's single. So he prays to the heavens to give him a wife, when a passing alien hears his wish and decides to help, Kurachi may have to think a little more exotically about him love life.

5) The Kind Hearted Roommate / Oshikake Hunter
Dorm head Hiroki never expected Kenta to come to his school. Hiroki always treated Kenta as a younger brother, but Kenta's feelings were far from brotherly, and he's not going to let Hiroki slip through his fingers again!

6) Dealing with Fate!
High school student Tetsuya has a really bad memory, especially first thing in the morning. This leads to a mix-up on the street and Okada Aki enters his life.

7) Diary of a Fantasy Life!

8) Love Making II
Tatsuya has started a new job at a college and Shinobu is lonely.

A short 4-koma about a girl with a mean look and her two new classmates.

Despite the content of their relationship, the delinquent Towa Aikawa is still a "friend" of the Student Council President, Mikado Shirahane. But today, Towa gets to sleep-in at Mikado's house for the very first time! Could their relationship advance into "lovers" now...!? List of Warui Series: Vol 1 Warui Koto Shitai [1-1] Vol 2 Waruiko Demo Ii? [1-2] Vol 3 Kirai ja nai Kedo [2-1] Vol 4 Koi Ja nai Kedo [2-2] --- Warui Koto Bakkashite Gomennasai [1-3 &/ 2-3] Vol 5 Warui Yatsu Demo Ii [1-4] Vol 6 Mujihi na Otoko [3-1] Vol 7 Warui Koibito ja Dame? [1-5] Vol 8 Kare ja nai kedo [2-4] Vol 9 Mujihi na Anata [3-2] Vol 10 Sunao ja nai Kedo [2-5]

From Shoujo Crusade: Akari always goes to a particular coffee shop, but not for their coffee. It's to see Naruse Hijiri-kun, a waiter who's totally Akari's type. And then suddenly one day she finds him waiting outside her school? Also includes: • Haru Koi Kaede has been trying to befriend her desk neighbour Muromachi Isami, but when she greeted him, he yelled at her?! In fact every time she greets him, he glares at her. Not giving up, Kaede tries to see the good (cute) side in him... • Power of Love Mikoto has always felt lonely ever since her parents divorced, but she starts living in a new family with a dad and a son in her age, Shou. As much as tries to have a happy family in her new home, Shou seems to be reluctant, but our happy-go-lucky Mikoto will not give up! • Flying Start! • Haru ni Kaze to Yuki ga Furu!

After ups and downs and lots of deep things went between, now the delinquent Towa Aikawa is a very "deeply involved friend" of the Student Council President, Mikado Shirahane. But when Towa visits Mikado's house for the very first time, Mikado's elder brother thought he was Mikado's sex-friend... List of Warui Series: Vol 1 Warui Koto Shitai [1-1] Vol 2 Warui ko Demo Ii? [1-2] Vol 3 Kirai ja nai Kedo [2-1] Vol 4 Koi Ja nai Kedo [2-2] --- Warui Koto Bakkashite Gomennasai [1-3 &/ 2-3] Vol 5 Warui Yatsu Demo Ii [1-4] Vol 6 Mujihi na Otoko [3-1] Vol 7 Warui Koibito ja Dame? [1-5] Vol 8 Kare ja nai kedo [2-4] Vol 9 Mujihi na Anata [3-2] Vol 10 Sunao ja nai Kedo [2-5]

From here:

The basic story: a high-school student (Nanase Hokuto) living away from his parents (who are in Australia) shares an apartment house with three older girls. His exposure to their whimsical and teasing nature leaves him pretty much despising females. However, the high-school idol (Taniyama Maina) ends up having a crush on him. Her best friend is Nakajima Atsumi, your typical sukeban. Hokuto's best friend, Moriyama Syuuichirou, is the young-punk biker. These two friends conspire to hook Hokuto up with Maina, much to Maina's delight and Hokuto's chagrin. Into this setting we interject the jealousy of the rest of the high school, a female rival for Hokuto's attention, a number of fights, the inevitable parents recalling Hokuto, and Maina threatening to run away from home. We could go on, but pretty much everything is in here.

Sequel of Kirai ja nai Kedo and Koi ja nai Kedo making it the third story of the Yuki-Shinonome series. As we left off from Koi ja nai Kedo Yuki has finally agreed to date Shinonome. But it seems he is having trouble thinking of Shinonome as his boyfriend. Will Shinonome once again be able to win over his lover's stubbornness and become real boyfriends with him? List of Warui Series: Vol 1 Warui Koto Shitai [1-1] Vol 2 Waruiko Demo Ii? [1-2] Vol 3 Kirai ja nai Kedo [2-1] Vol 4 Koi Ja nai Kedo [2-2] --- Warui Koto Bakkashite Gomennasai [1-3 & 2-3] Vol 5 Warui Yatsu Demo Ii [1-4] Vol 6 Mujihi na Otoko [3-1] Vol 7 Warui Koibito ja Dame? [1-5] Vol 8 Kare ja nai kedo [2-4] --- Warui ko Tachi no Bansan [1-6 & 2-5] Vol 9 Mujihi na Anata [3-2] Vol 10 Sunao ja nai Kedo [2-6] Vol 11 Mujihi na Karada [3-3] Vol 12 Warui Ouji Demo Suki [1-7]

1-4) About The Neighbor + Extra
That day, Miyata, who is still preparing for his university exam, got home and found not his brother, but an unknown man. That man, Shirai, has just moved into the neighbourhood. He looks at Miyata's messy test sheets and offers, "Shall I teach you?" With his airy smile and nearly perfect self, Shirai forcefully becomes Miyata's private tutor... and Miyata slowly becomes interested in Shirai... From Shinmakoku Scanlations

5) Unknown Words
Imaoka is a frivolous playboy, who might not be as frivolous as they say. Miki is a quiet boy who catches Imaoka's eyes and heart.

6) Unknown Name
Follow up about Imaoka and Miki

7) The Freezing Palm
Ishida has a dark secret about something he did in high school.. but 2 years later, he runs into his old teacher Mizushima-sensei - the person he wronged. Instead of being angry, Mizushima invites Ishida into his home... ?

8) Blindfolding Your Eyes Gently
What should I call you from now on? Continuation of Ishida and Mizushima, whom he now calls Motoi-san.

8.5) Sweet Fingertips
The Freezing Palm extra.

From Cinderella Story:

Matsuri Takanose a first year high school student. Her mother is the board chairman of the school, and Matsuri is under a lot of pressure to be the perfect student. One day after a grueling meeting in her mother's office at school, Matsuri encounters two boys who treat her differently. One is Takemasa Andou-kun, a smart, quiet guy who is known for keeping to himself and not talking much. The other is Watanuki-kun. Kaguya Watanuki is a very cute, outgoing, athletic guy. He and Andou-kun are classmates, but they don't appear to be friends. Later Matsuri happens to find out about her favorite idol pop singer and those two's relationship... This sets up an interesting love triangle...

Mia is a princess of the country where people are either masochistic (M) or sadistic (S), but generally only royalty is (S). Her daily duties consist of insulting, stepping on and generally bullying her people, and they're all happy about it! But the day comes when Mia has to transfer to a foreign country for a year to study there. The only problem is.... people there are normal. When Mia changes schools the (S) and (M) hilarity begins!

From Bakeneko Scanlations:

The barbequed meat shop owner, Yotsuya-san continues to harrass the part time worker Matsuda-kun saying “Your smell is special”. At first Matsuda-kun is baffled by this, but gradually he develops a liking towards Yotsuda-san…!?

Also includes a spin off of “17 Sai no Hisoka na Yokujou”- “Anata ga hoshii"

From Overload Scans:

Ayako, a normal high-school girl caught up in the experiment of an enigmatic genius, is divided in two. In the midst of the confusion of sharing her life, she remembers her sister who had died suddenly. What lies beyond the feelings she remembers and the feelings she’s forgotten…

Yurie Hitotsubashi was just an average middle school student living in the city of Onomichi on Japan's inland sea. She spent her days worrying about exams and trying to get Kenji, the clueless boy she likes, to notice her. Then during lunch one day she suddenly announces to her friend Mitsue that she had become a goddess the night before. Their classmate Matsuri quickly latches on to Yurie's newfound divinity as a way to promote her family's financially struggling Shinto shrine. She hopes that in replacing Yashima-sama, their ineffective local god, with Yurie, it will make the shrine more popular. Now all Yurie has to do is figure out what she's supposed to do with her power.

A bunch of school kids live in a world where people wear swimsuits all the time, as everyday clothing.

From MangaHelpers:
Ever since reading an article on a festival for the male genitalia, Mochizuki Yumeko can NOT stop thinking about the penis. It's not that she wants to have sex. She is just feeling this uncontrollable fascination with the penis. The only problem is that she has never seen a real penis. To satiate her obsession of witnessing a real penis, she looks into nude modeling. Now, she succeeded into convincing the timid, and only, member of her school's art club into nude modeling for her. Her journey into avant-garde male genitalia art beings.

Amagane Rinne, an up-beat schoolgirl, has died. Even though she is dead, she still has to go to school. But if she's dead, where would she go to school? In Hell, of course! But making friends in a school filled with demons isn't as easy as it sounds....which it doesn't sound...anyways, with dark artwork, and cool characters, this manga is a must-read!