From Clamp no Lumiere: Murikuri is the story of a popular pig, a pervert santa claus and his high school girlfriend, nice aliens and many more... It does not make sense and I would advise you to not try to understand it. Murikuri is to CLAMP what special halloween is to the Simpsons, a collection of short gags.

Hirayama, an aspiring manga writer, is thrilled to be chosen as a last minute replacement assistant for a celebrated manga writer he really admires. To his surprise, not only is his boss a woman, but she works semi-nude. In such a distracting environment, Hirayama must find a way to make a good showing of his ability.

Hot blooded manga about... writing manga. There are actually a few series starting with Moeyo Pen (Burning Pen), then later on came the sequel series Hoero Pen (Shouting Pen).

From Project Bite Me! Scanlations:

In a world where women are constantly wanting to kill themselves and insult the hard working women that work at Soapland, a single man rises up to stop them! Who is that man? That man with the super masculine form and a body of steel? It's none other than Nikutaikan-K! While he blindly rushes to their aid, maybe his first action should be to find out what is causing these women to want to die in the first place?

Adapted From Neon Genesis Evangelion. A short story in the lives of the young Evangelion pilots. One hot day, Shinji gets into a fight with his apartment-mate Asuka, due to her revealing clothing. Will Shinji be able to figure out how to patch things up with her?

From Mangascreener:
In a different world than the one we live in, a world where Japan is the lone superpower of the world, there is a wildly popular game show called the National Quiz. Every night, people dreaming of riches, fame, vengeance, and happiness compete on the show, for the chance to be granted a wish, any wish they have: the National Quiz has the power to make your wildest dreams come true. It also has the ability, if you lose, to make your life a living hell.

This is the story of K-i K-ichi (aka prisoner KK47331), a former actor-turned losing National Quiz contestant-turned wildly popular host of the show, and the people and events surrounding him.

The fate of the world rests on one man's shoulders. Or, to put it more exactly, it rests on his balls.
In a freak sealing accident the Queen of Terror is sealed into Satou Kohta's balls, thus preventing her from reigning destruction on the world. However, a lesser devil, the incompetent horned tsundere loli Elyse, has been sent up to Earth to release the Queen at all costs. The only way to do so is to make Kohta ejaculate, and Elyse only has 30 days to do it.
The battle for mankind has begun, in Kohta's pants.

Included stories: Ore x Yome: Himekawa is 26 years old and has a beautiful girlfriend who wants to remain a virgin until she's married. He's lied to her and told her that he has a career with a company when in fact he works at the local convenience store. Ashamed, and wishing to power up his career so he has a shot at actually marrying his girlfriend (and her virginity), Himekawa replies to a want ad and is surprised to get an immediate response. Gyakushu no Ore x Yome: Kou's very good with computer science and robotics, but not very skilled with the opposite sex. He has a crush on his coworker, Moe, but he hardly even speaks to her. Then one day, his 99 year old self from the future sends him back a present; an android of Moe that only wants to make him happy. His future self comes along for the ride, in the form of a little phallic robot. His new penis-bot and android girlfriend are definitely going to make his life a lot more complicated.

A man comes home one day to have his wife give him divorce papers. A woman comes home to her apartment one day to find a woman she doesn’t know wrapped in a towel coming out of the shower. They both get conned by the same real estate conman on the same house, a 4LDK. So now the man, his two sons, the woman, and her two daughters live in the same house.

A mysterious command arrives from a "King".
The life-threatening "Game" has now begun for the 32 students of the first year's B Class.
One day, all of the students in Nobuaki's class received their first message from someone calling themselves the "King", in which was written a baffling command.
That first command was very easy. However, the commands began to escalate until a life-threatening game had begun.
Failing to obey the orders leads to death!! Their friendships are being undermined by a bottomless terror!!

Shinjirou's brother is a brilliant scientist whose chosen career is making weird cell phones. Shinjirou has received a gift of his brother's latest product, the Doll-Phone, which is a walking, talking, tiny girl who doubles as a cell phone. But he can't help feeling that a phone like that seems kind of perverted to use...

[From AnimeWaves]:

Chinami was born with psychic powers. She has always wanted to join the Psycho Police Force. However, she doesn't know how to control her powers, so she failed the entry exam. However, after being saved from a psychic criminal, she joins the Psycho Merchants instead.

All of the girls at his college love Suou Tsukasa and come up to talk to him on a daily basis. Unfortunately for them, Tsukasa hates girls that are straightforward like that, but is too nice of a guy to tell them that.

In fact, he has a crush on Kizaki Megumu, his classmate and one of the shy and least talkative girls. The professor in one of the classes they have together is Dr. Hime, a young teacher whose childish looks and short height makes her a target for her students to jokingly tease and treat her more like their friend rather than a professor.

After taking home the drunk Dr. Hime, who was served lots of alcohol by her students, Tsukasa learns a giant secret about her love life.

(From Tranquil Spring) A comedy version of Simoun.

So just what is with this fascination for the Japanese teenage girl? We're talking about that extreme variant of her--that highly evolved creature of Japan's frantically trendy consumer culture... the ko-gal. Short Cuts is a unique and surreal Japanese comic strip that provides an illustrated journey into the ko-gal's world, created by Usamaru Furuya, one of Japan's most highly esteemed avant-garde comic artists.

Consists of six short stories spanning 14 years of Masanori's career.

• A MESSAGE TO YOU, RUDY

• ALL THE WAY DOWN

• Shiba Inu

• Gyangueiji

• Sand - SABAKU - Desert

• Even assassins laugh

Takafumi Ten is called to a mahjong club one night to play again Ikawa Hiroyuki, a young mahjong player. Having just robbed Ten's friends blind at mahjong, Ten arrives to take back his winnings.. Ten's mahjong style becomes more apparent as the game progresses...amateurish! Ten cheats in the last round, using a move called the Tsubame Gaeshi, and winning with a Tenhou hand. Hiroyuki is angered once Ten admits he cheated after the game. Will he come to understand Ten's "Way of Tenhou", where Ten willingly cheats and gets beat up in response for his friends? Will Ten unlock his true mahjong potential or cheat forever?

A short story about the demon king and her loyal servant, Aslia.

This is the story of a boy who one day walks into some strange wood and is saved by a nymphomaniac godess who can not only take over his body (turning it into hers in the process) but can also transform him into a girl.

Ryota plays it cool around all of his classmates, especially when it comes to girls. But he’s always the one on the spot in a perverted situation. In some of these many random anecdotes about the lives of fifth graders you'll find: peeping at collarbones, eating chalk, accidental skirt flipping, missing bloomers (you know, those girls' gym shorts things), and many others. Who says grade school can't have a high-school-type love story?