Big Sister, Little Brother is a 5-minute show that only airs on PBS Kids Sprout.
Is insanity hereditary? Shougo Mikadono's beginning to think so, because the terms of his late father's will seem crazy and following them may drive Shougo bonkers as well. Oh, it sounds simple at first: before Shougo can claim his VERY large inheritance, he just has to start attending a certain new school and find a nice girl to marry. It's a little unromantic, but perfectly do-able, right? After all, all the girls seem quite friendly, so all Shougo has to do is find one he has something in common with. Except, and here's the kicker, it turns out that Shougo has WAY too much in common with one of them, because she's actually his long-lost sister! And he has no idea which one she is! Will Shougo meet and court his Miss Right without committing something very morally wrong? Can he find his future bride without slipping into the wrong set of genes? And if his little sister does reveal herself, just how much will be revealed and under what circumstances?
Umaru is a renowned beautiful 16-year-old girl in town, living with her elder brother Taihei. She acts a perfect sister with a kind heart, intelligence and popularity, who everybody admires. So who would believe how true Umaru is at home? Sleeping, gaming, watching TV, eating junk food, drinking cola… that's almost all she does at home, leaving all the housework to her brother.
Suzuka Nagami is a beautiful third-year middle school student who has excellent grades and is the student council president. She wrote a novel about a little sister who dotes on her older brother, and the novel wins a light novel award. After they discuss the matter, Yuu is the one who debuts as a proxy light novel author instead of Suzuka, under the pen name Chikai Towano.
Oreimo follows the daily life of an ordinary high school boy named Kyousuke Kousaka. Kyousuke’s younger sister Kirino is a pretty fashion model, but also hides a dark secret of being an otaku of adult games. Kyousuke is the only person to whom Kirino reveals her hidden obsession and other issues.