Satoyama Katsuki is a carefree 15 year-old high school kid, and a pretty lazy one at that. However, he secretly has a crush on a girl who happens to share his name: Mizutani Katsuki. Upon finding out that Mizutani's father used to be a pro-boxer, and she herself infatuated with the sport, he reluctantly joins a boxing gym in order to impress Mizutani. Satoyama is quick to find out he may have the blood of a genius boxer running through his veins...

Tsuna comes home one day, only to be greeted by a little baby mafioso who apparently is his new home tutor. His job is to guide Tsuna into his role as the 10th Boss of the Vongola mafia family. With the help of all his new friends and an array of special items such as the "Dying Will Bullet", he might just be able to do it.

This man's name is Gota Araki. Today he begins working as a teacher at Kyokuran High School in the city of Tachibana. His hobbies are fitness and clipping pictures from adult magazines. But another man has been sent to teach at this high school and that man's name is...

King Panda is dead and the Upper Yard of the Zoo is left without a ruler. The animals of the East jockey for domination while the peaceful animals of the West prepare for the oncoming war. It's the cutest and funniest animal civil war you'll ever see!

Fuyuki is an anti-terrorism specialist for a security company. His current assignment is as a bodyguard for elite company president Kagami. This is no ordinary assignment, however. Kagami’s not looking for protection from Fuyuki, he’s looking for love, and his constant expressions of affection have Kagami’s nerves stretched to the breaking point.

Kirara hunts Kagari the White Wolf, who is believed to have killed villagers, travelers, and her older brother.

From Yen Press

Soon after his birth as a Nobody, Roxas joins the mysterious Organization XIII, knowing nothing of his identity. With the help of Axel, another member of the Organization, and the mysterious No. 14, who is also missing her memories, Roxas slowly begins to learn what it takes to be a part of Organization XIII…and what it means to have a heart.

One day, high school girl Sonoko forgets something so she goes back to get it. She glances out the window and sees a boy in the schoolyard, surrounded by unconscious and bleeding bodies!
The boy is Narusawa, and blood runs down his cheek, and he has a dangerous look in his eye. He is one of the toughest guys in the school, and had beaten up the guys at his feet. He senses Sonoko looking at him and turns to her.
Sonoko's school is co-ed, but the girls only have classes with girls, and guys with guys. At this school, most of the guys are the loud, rude, dangerous, violent gang-member type. Most of the girls know to stay far away from them.
But, things are about to change when this kind of boy asks her to be his girlfriend--the dangerous Narusawa-kun himself! He waits for Sonoko after school and follows her around. He seems to really like her! What should she do?
Narusawa has a different side to him that he is willing to share with Sonoko. He can be kind and funny. What a strange couple they would make! There are a lot of obstacles in their path to love. Narusawa is willing to tackle them, but can Sonoko face her own fears?

Oneshot/Chapter 0 : Vulcan Markovic lives in a small fishing village in Croatia. He has only two things on his mind--designer goods and losing his virginity. When an indescribably beautiful girl shows up asking for directions to Heaven's Gate, Vulcan takes his first step into "thrilling world-salvation action!!"
Chapter 1 : Main chara switched to another apostle (a monk).
Chapter 2 : On to another, with recurring previous main chara.

From Endless Abyss:

The Law of Ueki plus takes place 2 years after the end of The Law of Ueki, everyone has gone there own way and life has become peaceful again until one day Ueki saves a dog only to stumble upon a plot to steal the memories from all the people of earth. Ueki as the only person who did not have his memories taken, must go into a new world and retrieve the stolen memories where new allies, foes and powers await.

A group of powerful beings called tenkaijin are holding a special tournament. The rules of the game--each tenkaijin selects a kid in junior high to be his champion and grants him a special power. The kids take each other on in heated battle, but if they hurt innocent bystanders, then they lose one of their natural-given abilities. Every time they win a battle, they gain a new ability. The ultimate winner of the tournament is granted any power of his choosing, and the tenkajin who he represents succeeds in becoming the next god. Kosuke Ueki has been chosen to fight in the tournament. His special power--the ability to turn garbage into trees.

Strippers try to stop a zombie infestation.

Mazinger Angels chronicles the adventures of four women who pilot giant robots in the Mazinger vein. The concept is a spoof on the late 70's and early 80's popular TV series Charlie's Angels.

Three of the robots, Aphrodite A, Diana A and Minerva X are from the original Mazinger Z series, while Venus A is from the Great Mazinger series. Their pilots are also traditional characters from Go Nagai's universe, Sayaka Yumi and Jun Hono from Mazinger Z and Great Mazinger respectively, and Hikaru Makiba and Maria Fleed from Grendizer.

The style of the manga highlights the sex appeal of both the characters and the mechas, sometimes similarly to the way Aika's female characters are shown. (taken from wikipedia)

From CPM:

An alien armada from Jupiter has amassed enough power to destroy all of Earth's defences. Earth's final hope lies in the Space Battleship Nadesico, a ship created using recently discovered extraterrestrial technology.
Can the Nadesico's rag-tag crew overcome their idiosyncrasies and defeat the alien fleet, or will Earth's last hope be lost?

The manga differs greatly from the anime

[From Viz]:

Ginta Toramizu is a 14-year-old kid who doesn't have a lot going for him: he's near-sighted, doesn't do well in school, sucks at sports, and to top it off--he's short! But Ginta is a dreamer and has had the same dream 102 times, always in the same fantasy world, where he is a hero blessed with all the abilities he lacks in real life.

Then one day a supernatural figure appears at Ginta's school and summons him to a mysterious and exciting new world! In this strange universe filled with magic and wonder, he is strong, tough, agile--and he can see without his glasses! Thus, Ginta begins a mystical quest in search of the magical items known as "ÄRMS," one of which may have the power to send him home. Joining him on this epic journey are his companion Jack and the valuable living, talking, mustachioed iron-ball weapon known as "Babbo," which everyone wants but, it seems, only Ginta can possess!

From Aerandria Scans:

The kingdom of Gulba is racked by rebellion against its young prince. A special guard has been formed to protect the realm against the rebels. They are led by Captain Carla, the Beast Tamer. And her "beast" is tall handsome Hazel, her aide and bodyguard--and the only one she trusts. Vowing to avenge her father's death at rebel hands, Carla rescues Hazel from a circus to raise and train herself. The rebels have stepped up their attacks, there's a traitor in the guard ranks, and now Hazel is acting strangely. Can she really trust him after all...?

Akira Nikaido is a typical slacker high school student who thinks he has a normal life--until a mysterious man called Shirogane appears and tells him to meet him at the school that night. He is skeptical but goes anyway... and gets attacked by a shadow monster! Shirogane convinces him that the balance between the human world and the shadow world has been distorted, and that Akira must become a shin--a creature of the shadow world--in order to help restore the balance.

From Tokyopop: Nanaki survives a car accident to discover he is psychic. Recruited into an organization that solves cases with psychic powers, Nanaki's average life quickly turns into one of adventure and intrigue. Slacker Nanaki Shunsuke's life is turned upside down when he's hit by a bank robber's car and later meets a strange boy who claims that the accident caused Nanaki to develop psychic powers and that he is required to join LOCK, a paranormal investigations agency or be the suspect of any and every suspicious case that turns up. (thought a summary and categories were need since there weren't any :P If your into Shonen it's a good read :P Sirenic Griffin){Corrections by Silvermagic}

From Seven Seas:

Death Jr. -- you've played HIS PSP game, you've read HIS comic! Now get ready as we turn the tables and shine the spotlight on a force as powerful as the son of Death himself -- his girlfriend!

Pandora discovers a secret portal that sends her to the future and into the body of her teenage self. Besides having to grapple with teenage angst, she must save the future DJ from his greatest enemy yet -- a snake-haired foreign exchange student with a deadly gaze and even deadlier intentions!