Chapter 41.5
It's about the married life between a newlywed working otaku and his pregnant wife.
Chapter 0
Genshiken follows the lives of a group of college students drawn together by their shared hobbies, and the trials and adventures associated with being otaku.Genshiken Nidaime ("Second Generation") is a continuation of the previous series, with chapter numbering starting at 56. In the Japanese edition, the first volume of Nidaime is numbered Volume 10, to continue from the end of the 9-volume Genshiken series. The US edition renumbers the volumes so that the "Second Season" starts with Volume 1.
Chapter 7.5
From Del Rey: Chihiro has been cursed with bad luck all his life, but all that changes when he wins a mysterious lottery that earns him a spot at the prestigious Rikkyoin High School, a strange place where everything is decided by chance - even who gets appointed to the student council. Although Chihiro has drawn the winning ticket, this is no ordinary honor. Each day the student-council members must risk their lives to save the school from various forces of evil.