Detroit Metal City is about a death metal band that has gained immense popularity in the indie scene.
The main character is a push-over, Negishi Souichi, who is trying to make a living in the music world, but he didn't imagine in his wildest dreams that it would be in such a band. Read and see what hilarious situations he gets himself into.

From J-Wiki:
Takashi is reunited with a childhood friend he has not seen in 13 years named Miriko. Miriko, while thought to be missing, became the queen of an alien planet and leader of a strange army corp. To keep a childhood promise, Miriko sets out to take over the world with Takashi. However, Takashi has no desire to do this, so Takashi must stop Miriko's wild behaviors.

From Viz:
A hopeless geek, a beautiful woman, and a fast connection--could the Internet be his ticket onto the express train to romance?
A real-life thread on an Internet forum sparks a nationwide phenomenon! A nerdy otaku meets a girl on a train and posts an urgent query on the Web--How the heck do you talk to girls? What should he wear on their date? Where should they go? The forum's response was overwhelming, and the thread continued to grow along with their relationship.

From Dan of Population GO:

Three friends, Kotori, Yuuto, and Rin are trapped in school when the principal halfheartedly summons a horde of demons. The demons make a pact with each student in exchange for possessing them. Most of the students wished to be be good looking or to have longer legs, but Yuuto manages to stave off the possessed student body while Rin overpowers the weak demon possessing her. Yuuto makes a pact with a demon to return the school to normal, but what will happen to the school now that each student is being possessed by a demon?

Doujin Market. It is a place where individuals sell their self-published books. Each participant works daily to achieve their personal goals.

While their are some who obtain their dreams, there are also those who get pounded by reality. This is the story of those who live in the world of Doujin.

Tsuchie Takeshi has dreams of when he played with Hikari-chan as a child. He remembers her as a kind, sweet girl. However, one day on the way home from school, Takeshi is abducted and taken to a huge house, only to find out that she's become an arrogant, violent dominatrix (emphasis on violent). Furthermore, she says that he promised to marry her! How will he adjust to her new personality, and living with her as a new son of her prestigious family?

Izumi, a young art student goes to visit her old professor who is living out in the country. Izumi is trying to get away from something and wants to take a break at the professor's house for a while. When she stumbles on Sensei's secret sexual fetish, it sets off a tense relationship full of awkward moments and weird demands.

" Victim - using the latest and greatest technological advances, you can now enter the game world; a revolution in gaming experience!...."

What does it feel like to be a game character? Why are massacres in the game world considered enjoyable? Amusing? Relaxing? Come and read this short, full-color oneshot by a Singaporean mangaka, Foo Swee Chin, where game creators explore the minds of the game characters by going inside their virtual game. [ruggia]

Echo-Pun is a 4-koma about Eiko and Haruka, two childhood friends who loved superheroes and pretended to be heroes while playing together. While in grade school, Eiko had to move away, but the two promised to meet up again in high school and become superheroes for real.

Haruka grows up into a normal girl, and upon entering high school, she suddenly meets her old friend Eiko. Eiko, however, is wearing a costume, fighting bullies, and calling herself Echo, a superhero. Haruka tries to keep Eiko out of trouble with both the bad guys and the disciplinary committee president, a girl named Kamikaze Shiori who, for some reason, seems quite interested in Eiko.

Can Haruka lead her old friend to the stable side of society, or will Echo drag Haruka further into the world of alter egos, costumes, and justice than she's ever gone before?

To cure his persistent virginity, Yuuto Mutsura joins his friend Naota in a trip to Aqua Eden, the "City-by-the-Sea", where brothels are allowed. Before he has a chance to become man, he is separated from his friend and accidentally turned into a vampire! Now forbidden to leave the city and forced to participate in a Public Morals task force with several beauties, how will Yuuto handle this new life?

From SCX-Scans:

It tells the story of a couple, both very innocent and in love with each other, who are now living together! Takeshi is a pure-hearted college student who is enticed by his girlfriend that has run away to live with him. Temptations ensue.

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?

A woman F.P. Ageha helps people in their problems.

From Tokyopop:
In the year 184, three leaders (Yoobe, Kwanoo, and Jangbe) rose up against the oppressive Chinese government and were all killed. Now, a 17-year-old shaman by the name of Aram Ko is in search of the reincarnations of the three men. Back in the year 184, Kwanoo had saved a man's life and, in return, that man ensured that every one of Kwanoo's female descendants became a Shaman so that they could serve Kwanoo when he is reincarnated.

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!

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!

Fortune Arterial's story revolves around the male protagonist Kohei Hasekura, who transfers into a prestigious public school--an English style six-year school, serving junior high and high school students. The school, named Shuchikan Academy, is on an island, Tamatsu Island, off-shore from mainland Japan, and the only way to get there is by boat. This is a series of characters' introductions to prelude the main story.

Naota's life isn't simple: he lives with his eccentric father and grandfather in a two-story house above a family-owned bakery in a town marked by a gigantic factory at its heart. The factory looks suspiciously like a hand iron, complete with a steam release at the top--not the most typical landmark. Life is already strange enough, but to top it off, his older brother's ex-girlfriend starts making extremely suggestive passes at him... and an impish, playful alien smacks him in the head with a bass guitar and then infuses herself into his family.

Jiga Kirishima lives in a time where the only sky the people know is the color gray and most of the world is wasteland and ruins, with a few people in power depriving resources from the disorganized weak and poor majority. With his father's sword, Jiga makes friends and enemies and goes on adventures while searching for others who share his bloodline.
Jiga's sword happens to be made of a rare material which a powerful organization known as Lost Eagle Nest claims to want in order to rebuild the world, but is that what they really want it for? They'll stop at nothing to take it from him, and Jiga and his friends now have a price on their heads.