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Trivia
Some items and phrases in the Ouran anime make some allusions to other anime series (most of them also from Bones) such as in episode eleven, when Renge said that "Even Edward dealt with a cross with willpower and guts", probably talking about Edward Elric from Fullmetal Alchemist, and the burden he carried since the day he and his brother Alphonse failed to resurrect their mother using alchemy, when he lost an arm and leg and Al had his soul attached to a suit of armor.
Episode 4
Kyouya tells that the director had filmed the blockbuster "Sennen no Yuki", a vampire movie. "Sennen no yuki" is the name of another manga made by Bisco Hatori.
Episode 7
Renge wears a bikini to show off the tattoo of Quon Kisaragi from RahXephon. Coincidentally, Reika Mishima, a character from RahXephon is also voiced by Maaya Sakamoto (the voice actress for Haruhi).
Episode 9
Renge "cosplays" Yomiko Readman from Read or Die.
Episode 11
When Renge is "reprogramming" Nekozawa, she has Mori write down a list of things Nekozawa's not allowed to say. Some of the words and phrases included are "cursed video" and "Tohru-chan".
Episode 12
Hunny's response to being woken up early (according to Tamaki and the twins) is apparently a Bunny version of Eureka Seven's Seven Swell phenomenon.
Episode 14
Tamaki, at one point during a game, kicks a mari, making it travel at amazingly high speeds and causing it to hit the newspaper club's chairman on the head. This is probably in reference to Detective Conan (known as Case Closed in English), an anime in which the main character, Conan Edogawa (a synonym for Shin'ichi Kudo, who is known as Jimmy Kudo in the English-language versions) often uses high tech shoes to kick kettles or soccerballs into the faces of his enemies to knock them out.
Episode 16
Another Fullmetal Alchemist reference occurs when Hikaru shows a ball surprising Haruhi, which resembles Ed's head with his sharp-looking eyes and his characteristic "hair antenna".
Episode 22
The wall Tetsuya sits in front of has the Bones logo on it.
The theme of the day in the Host Club has them dressing up like samurai from the time of the Bakumatsu. Tamaki almost looks like a blonde Himura Kenshin, though he is actually cosplaying Sakamoto Ryoma, and Haruhi is said to look like Okita Sōji, the person that Nobuhiro Watsuki patterned Seta Soujirou after.
Pop culture
There are plenty of pop culture references in the anime as well. For example, Kyouya's laptop is silver and has a pineapple logo on the back of the monitor, alluding to Apple Computers. Renge plays the game Ukidoki Memorial, a play on Tokimeki Memorial, with a controller featuring the distinct (and now abandoned) PS3 boomerang design. The twins are seen playing a GBA SP in flashbacks, and play a Nintendo DS Lite in the present timeline.
