All spoilers are unmarked.
- Episode 3: Kyousuke, in order to protect his sister's porn, admits to his father that he's the owner of the games. And it comes out this way:Kyousuke's father: You were in your sister's room, using your sister's computer to play a game about doing indecent things to your sister?
Kyousuke: It was really amazing. Got a problem with that? What's wrong with a high schooler having eroge? ... I'm not throwing this away! I'll defend this to the death!
Kyousuke: Listen up, old man! I LIKE ANIME AND EROGE WITH A PASSION! I can say that I love them! If I throw this away, I won't be me anymore! EROGE ARE MY SOUL! YOU HEAR MEEEEE!!!!????
*gets punched in the face*
- Manga Chapter 19: At Summer Comiket, Kyousuke is given a maid-themed erotic doujin by an author dressed as a maid. As he reads it, Kyousuke can't help but think that she based the heroine on herself, but when he asks the author about this, Kirino appears out of nowhere, kicks him to the ground, and starts furiously stomping him while accusing him of sexual harassment. When the siblings look back at the author, however, they find her excitedly sketching them and declaring that her next work will feature S&M incest. Needless to say, Kirino is not pleased.
- Episode 5: Kyousuke, in order to help goes to his father to ask him for information regarding a certain incident. His father gives him that information, but first says, "I coincidentally happened to research [the incident] recently. Don't misunderstand; I'm not doing it for the sake of you two." In other words, Kyousuke's father is Tsundere for his children.
- Episode 6: Manami offers to let Kyousuke take a bath after her father gets out. He declines, instead wanting her to go first. Manami comes up with the brilliant plan of offering to take a bath together as a joke, clearly not anticipating his mastery of Refuge in Audacity. Further, everyone else seems to be okay with this idea.
- Also from Episode 6: Kirino squeeing and rolling around with the hugging-pillow she purchased online.
- MANAMI: Kyou-chan, Dad's about to get out of the bath. Do you want to take one next?KYOUSUKE: I can go last. You take one first.MANAMI: I'm fine going after you.KYOUSUKE: No, you take one first.MANAMI thinks, then claps her hands together, smiling.MANAMI walks over to KYOUSUKE giggling quietly, leans against his back and whispers into his ear:MANAMI: The how about taking one together?KYOUSUKE is suprised and turns around. MANAMI laughs at him.MANAMI: Kyou-chan, you're blushing!KYOUSUKE gathers himself and turns around again.KYOUSUKE: Alright! Let's take one together!MANAMI is greatly shocked, and backs up, holding her arms. IWAO strums the shamisen.MANAMI: Seriously?KYOUSUKE: Super serious! You already invited me. You can't take it back now, can you?IWAO: An-chan, you're a real man!KYOUSUKE: I know, right?IWAO: Damn! So cool!IWAO strums the shamisen again.KYOUSUKE stands up, shot is taken from below, high perspective, with his groin in the center of the screen.MANAMI falls back with a gasp, even more shocked and blushing furiously, then crawls over to the door wimpering, opens it, and yells out:MANAMI: Grandma, what do I do? Kyou-chan wants to take a bath with me!KYOUSUKE: Don't go telling everyone!GRANDMA opens the other door to the room and leans in.GRANDMA: So take one with him.KYOUSUKE sweatdrops.KYOUSUKE: Wha-it was a joke!GRANDPA peeks out from under the table. MANAMI is looking over her shoulder back at KYOUSUKEGRANDPA: You so want to, too.KYOUSUKE: I don't.
- Episode 11: Kirino lays a trap in Kyousuke's room where he has hidden pretty much all the eroge he had. The first thing he sees is the computer on with a picture of an Imouto H-Game, he put away a long time ago. So while he freaks out about that, it gets worse. Manami finds his porn books scattered around, and wouldn't you believe it, it's freaking Meganekko books. Kyousuke hits the emergency button, and a spectacled girl pops up and text flies on screen saying, "Onii-chan is a pervert!!!!". All Manami can do is say, "Would you like me to call you Onii-chan?" Cue Sound-Only Death scream.
- Episode 11: Kuroneko is showing Kyousuke, Kirino, and Saori a doujinshi manga she recently made. Right off the bat Kirino takes issue with the fact that the two main characters look exactly like her and Kyousuke, but Kuroneko assures her that while she did use them as models, the only other similarity is that the characters are siblings. Hilarity ensues when the next page features not-Kirino passionately sniffing not-Kyousuke's boxers:Kyousuke and Kirino: Stop right there!Kuroneko: What's wrong?Kyousuke: You know exactly what's wrong!Kirino: There are limits to what you can and can't do in manga!Kuroneko: Why are you getting so angry? My only intention was to write a fictional story. When you react like that, you make it seem as though I may have accidentally reflected reality.Kyousuke (to Kirino): Don't tell me you really do sniff-Kirino: I DON'T! This is just in a manga!
- Even funnier when you take into account that in the very next episode Kyousuke goes to a midnight release in order to get Kirino an Eroge about a girl who is obsessed with her older brother's underwear!
- What's more is that Kuroneko didn't stop there. Within the next two pages, not-Kirino raids her brother's Porn Stash (which includes a highly suggestive picture of not-Manami) and complains when she finds that he doesn't have any little sister-themed magazines. It's at this point that Kirino (the real one) decides to pull the plug.
- Episode 12: As part of Kirino's last life counseling session with him, she asks Kyousuke to get an eroge for her at a midnight release in Akiba. He runs into... his male classmate, Akagi, who is also trying to get the game that his little sister also wants him to get for her! They agree to honorably keep this little meeting a secret from the rest of their classmates. ...then the line they are waiting on opens up, and Akagi heads over to the line next to him... for a "homo" game whose artwork is most likely inspired by Cho Aniki. The sound effect scream when it gets presented absolutely sells the scene.
- Episode 13: When visiting the game research club with Kuroneko, Kyousuke meets Akagi Sena, a rather uptight first-year. With a well-placed question, he manages to out her as both a fujoshi and as the little sister of his classmate, Akagi. Hilarity Ensues. Kuroneko even baits her with a remark about Shipping, leading to Sena letting slip that she ships her fellow (male) gaming club members. They're all present when she says this, and their reaction is priceless.
- Akagi Sena's "Dungeon Explorer RPG", and the club's rather appropriate reactions.
- Just about every one of the bonus animated commentaries are almost guaranteed to leave the viewer in stitches. In particular, the entire episode 05 commentary featuring Kyosuke and Kanako is nothing short of pure comic gold.
- To give you an idea, the start of the very first one is Kirino and Kyosuke introducing the concept, messing around, and Kirino telling Kyosuke he has to find something nice to say about the episode/about her. Then Kirino takes a nice long cool drink of juice and the scene where Kirino's scooting around under Kyosuke's bed with her butt in the air is on screen.Kyosuke: [Watching Kirino drink] ...Nice ass.
Kirino: [Extensive spit-take] What the hell, dude?!
- It only gets funnier from there.
- To give you an idea, the start of the very first one is Kirino and Kyosuke introducing the concept, messing around, and Kirino telling Kyosuke he has to find something nice to say about the episode/about her. Then Kirino takes a nice long cool drink of juice and the scene where Kirino's scooting around under Kyosuke's bed with her butt in the air is on screen.
- The absolute clusterfuck that occurs when Kyousuke and Kuroneko reveal that they're dating:Sena: Don't tell me you thought we didn't realize that [long ago]?Kyousuke: ... I only just started dating her yesterday...Makabe: Kyousuke, you mean you seriously weren't dating [Kuroneko] before?!Gennosuke: You mean you two have started dating?!Mikagami: Kyousuke! You mean you weren't dating your sister?!Mikagami: You mean you weren't?! You said you wanted to touch your girlfriend's boobs, so I thought...!Sena: Kousaka-senpai! What's this about you going out with your sister?!Kyousuke: That's what I want to know—Kuroneko: SENPAI.Kyosuke: —urghk...Kuroneko: Something about that last conversation has made me very curious. Care to explain it?'Kyousuke screams in anguish.