A planet-threatening space disease, the "demon flu", has infected an inhabitant of Earth, and a space doctor is needed! The Space Medical Bureau has chosen Dr. Rurru for the job, but -- unfortunately for Minao Hitoharu, the infected patient -- she has a tendency to mishear and misspeak (with a mind towards ecchi) to comical effect.

Features Illya as a main character where she's living an alternate life as a school girl. However, she is chosen by the Magical Stick Ruby and is involved in a quarrel between Rin (Kaleido Ruby) and Luvia (Kaleido Sapphire).

Just before entering the university, Yanagiba Masahiko's father died in a car accident. His mother died when he was four, which makes him now really an orphan. But even before the death of his father, he didn't have a family life, as his father was always busy or abroad.

When his mother's younger brother and his wife decide to invite him to live with their family, his life takes a turn. But it is not going to be the normal family life he is imagining for himself. What is the "terrible" secret that led his parents to break the bonds with his aunt and uncle? What could be the true nature of his cousin, Shion? And last but not least, will this "terrible" secret eventually get Yanagiba, too?

Onizaki Teppei is a high-school freshman who just wants to live a plain student life, but his world is rudely shaken by a mysterious girl, Mitogawa Enma, who declares her intent to find a husband at the school!

Sousuke is the class president, and is a stickler for the rules. Lately, he's had lots of problems. First of all, he's got to deal with his cute, but unruly, childhood friend Miroku. Secondly, they have a new transfer student, Enma, who claims to be from hell. Enma refuses to follow any rules but his own. Lastly, there's the giant, mysterious claw marks that have been appearing all over school buildings. With all this trouble going on, will Sousuke follow the rules or learn that sometimes there are more important things?

From ryColaa:
Our hero, who doesn't know how to swim, joins his school swimming club and begins to learn from their star swimmer who loves swimming more than anything. Good thing she's cute and nice to boot!

From Tokyopop:
Aliens have landed on Earth and are now a normal part of society. These beautiful beings have been given the name "DearS" and are trusted and welcomed by most humans. In order for the "DearS" to learn Earth's customs, they are sent to random high schools to "home-stay." When Takeya helps a DearS in his school, she calls him "Master." Thus begins the humorous life of Takeya and his sexy alien follower, Ren, who tries to figure out the wacky customs of this place called Earth!

From Tokyopop:
Hideki's just like every other guy in the 22nd century. He just wants a good job, a good car, and a sexy robot girlfriend to call his own. Until he lands a job, he'll never be able to afford his own 'Persocom' companion. Hideki's luck changes when he discovers Chi--an adorable but seemingly stupid Persocom--tied up in a pile of trash. His first robot companion turns out to be a lot more responsibility than he expected, and she gets him into quite a few embarrassing situations. It's 'boy-meets-girl' for the cyber age.

From Wikipedia:

Shimeru Futaba is a normal high schooler living a normal life, active in his school's wrestling club and slowly getting closer to his awkward love interest, Misaki. This fails to last, as he discovers his family's hereditary genetic defect that becomes active at adolescence. Although it will eventually become controllable, excitement and stress now make Futaba switch sex. Hilarity ensues.

From Village Idiot:
What will happen to an ordinary human teacher who falls into a youkai school, with his only ally(?) a sexy but air-headed nekomata? A slight ecchi and heartwarming read brought to you by the author of “Sore wa Totsuzen, Unmei no Aite ga”

A short story about a cat demon and a teacher.

Loner high school student Moribe Kyouya thought he was lucky to have the beautiful and mysterious new transfer student Baroque talk to him. The next thing he knows, he receives a love letter calling him to the roof, but the confession isn't exactly what he expected...

Atori has an unusual part-time job... she’s a demon hunter! After school, she hunts demons for a mysterious organization named N.U.E. To kill her enemies, she unsheathes the saber hidden within her hair. However, Atori is actually half-demon, but she has forgotten her past. Despite this, she's been able to overcome many difficulties as well as befriend those from both species. Unfortunately, her once calm life is beginning to quake as a terrible shadow now looms over her...

Late one night when Jun was out on his bike, he came across a drunk, half-naked girl sprawled on the side of the road. She came to just enough to be uncomfortably affectionate, but Jun took her to his home to sleep it off with gentlemanly discretion. It turns out that she is Kawase Narumi, his author mother's new assistant. Unfortunately, she has no idea what she's doing in her new job, so Jun's going to have to coach her. He's also going to have to deal with her habit of getting drunk, mostly naked, and cuddly. Jun's life will never be the same! [From Baka-Updates]

Kyousuke wants to be a cop. Because of that, he always tries to do the right thing and help others out. Well, while saving a girl from some bullies, they end up liking each other. Not to soon after, she needs saving again, and he ends up with woman's panties over his head, giving him super strength (pumped with horniness.) Not your normal super hero.

Yona Ryouma, a normal high school boy, saves a man from another world at the cost of his own life when a mysterious earthquake occurs. The man, Emillio, uses a potion which apparently saves Ryouma's life. However, he is also changed into a girl in the process.

Emillio is actually the prince of this alternate world and he declares Ryouma as his wife, presumably on the context of saving his life. But what about Ryouma's life as a high school boy in his own world? And will he come to accept being the prince's wife?

Goto Nagi has travelled to the southern island of Okitsushima, and ventures out to see Umi no Misaki, a striking cape jutting out into the ocean. But when he arrives, he finds that there is much more to this cape than a wondrous view. There is something peculiar about the cape, and about the island's inhabitants.

This adaptation focus on each heroine based on the Amagami visual novel.

V.1 - NANASAKI Ai
V.2 - MORISHIMA Haruka
V.3 - SAKURAI Rihoko

Read some slice of Asuka-chan's normal life. And see how interesting some daily activites of a cute high schooler girl can be.

Yukinari Takase is a huge masochist who instantly takes a liking to Rion Tachibana, a menacing trap who just transferred into his class. After Rion believes Takase has uncovered his secret, he decides to make Takase his servant in order to keep his mouth shut.

In the 30th century A.D., in a world in which magic exists, 100 years have passed since the human race won a war against the Devil King. Even though the war caused many sacrifices, slowly but surely civilizations began to rise again.
One day, a virtuous child named Sai Akuto ("Worst Evil") is adopted from the orphanage he's lived in ever since a witch quietly left him at the church as a baby.
Five years later, Akuto passes the test to enter Constantin Magic High School. But after arriving and taking the vocational aptitude test, Akuto receives surprising results:
Examination Numbers: Number 021
Name: Sai Akuto
Future Occupation: The Devil King