If you liked the Genshiken anime, the Anime-Planet community thinks you'd like:
The studious and uptight Chiaki is well-known as the top pianist of his school, and dreams of becoming a world-class conductor like his idol, Viera; but his fear of flying (which makes studying abroad impossible) combined with a recent break-up and dismissal from his piano instructor causes that future to seem both bleak and unlikely. After collapsing outside of his apartment, drunk, Chiaki inadvertently meets a young woman named Nodame who, while quite talented at the piano, is unclean, clumsy, and haphazard. Despite being almost polar opposites, the two begin to grow closer and work, together, to overcome the obstacles in their careers.
Ouran High is a school for the extremely wealthy or, in Haruhi's case, the extremely talented. But no amount of talent will help when Haruhi accidentally drops an eight million yen vase in a music room. The vase was the property of Ouran High School Host Club, a group of attractive young men who, for a fee, provide their time and affections for their lovesick clientele: the female students. Fascinated by this strange new specimen, a poor and clumsy commoner, they force Haruhi to work for them until the debt is repaid; but they get a lot more than they bargained for...
Genshiken and OHSHC are both about after-school clubs, but more importantly, the key theme is assimilation. The type of assimilation is where Genshiken and OHSHC diverge. Genshiken follows an otaku, Sasahara, who joins a club of his own free will, and the reason for joining: the members are all otaku just like him! As a contrast, the intelligent and socially inept Haruhi (of OHSHC) is forced into the Host Club against her will as a result of an unfortunate accident, and to top things off, must hang around (seemingly dimwitted) social butterflies and pose as, well, something she's not. Both series are filled with humor and awkward situations, so you never have to wait for a good laugh.
The anime and cosplay-loving Sakura Nankyoku – known by her peers as Penguin at her old school – has just moved to a new location. After suddenly becoming student council president, she finds herself in the middle of many bizarre and ecchi situations. Panties fly, transformations are plentiful and the day is never dull in the life of Sakura, her third-grade sister Kaede, her tomboy rival Kujira, Cha Chi from China (who wants nothing more than to be Kujira's "boyfriend"), and more!
Both animes are about otakus and how they live between no otakus, while in penguin musume heart theres only one otaku and its more sweet and funny, both animes have the same feeling and they both show the daylife of otakus and also they make lots of parodies of others animes and talk a lot about the common things that are usually on animes, like costumes of maids, cats, etc. And also they talk about cosplay and even the characters do cosplay sometimes.
Life is simply not worth living for down and out school teacher Itoshiki Nozomu. He has no hope of progress, no prospect of promotion, no chance at happiness… he is in despair! Even his name spells 'zetsubou' – 'despair', when compressed. But when the time comes to end it all, Itoshiki's attempted suicide on the first day of the new school year is foiled by relentlessly positive Fuura Kafuka. This saves Itoshiki long enough to meet his new class, and the quirky range of students under his care. Will Itoshiki Nozomu depress his students with his anguish? Or will Fuura show Zetsubou-sensei the joys of life and hope?
Both Sayonara Zetsubou Sensei and Genshiken are somewhat random and definitely include a lot of self-effacing humor. Here are some points to consider :
There’s never a dull day in lives of the Hekiyou Academy student council! President Kurimu has a sweet tooth and neglects her duties with ease, while secretary Chizuru skillfully manipulates those around her. Otaku Mafuyu obsesses over writing online walkthroughs, and is constantly hounded by Ken, the only male of their crew and an eroge addict who has the ultimate goal to turn the entire council into his harem. Luckily for Mafuyu she’s protected from his advances by Minatsu, her sporty and tomboyish sister! Together, the five repeatedly struggle in their fight against boredom, making constant otaku references and fighting against the journalism club along the way!
Both shows have reference to the otaku culture. While Seizon explodes with randimosity and lacks a 4rd wall completely, Genshiken follows a more passive depiction of a group of kids who enjoy anime/manga related stuff.