This dialog from the Ryuki World arc. The set-up: Natsumi has been falsely accused of murder, and Tsukasa, despite making jokes about her being a cold-blooded killer, is trying to save her - except that in this world, legal cases are decided with Rider battles.
Zolda: I won't let an amateur make the verdict! She's guilty! Guilty! (fires giant shoulder cannons)
Tsukasa: Who the heck's that?!
Ren: Probably the public prosecutor.
Tsukasa: Suddenly I very much want to prove her innocence.
The whole Den-O episodes counts, starting with the whole getting possessed thing, up to the climax, where Kuuga mistakes Den-O Momotaros for the enemy, kicking him on the neck, down to the bad guy breaking character and telling them to get their acts together, finally culminating in Momotaros' and Kuuga's..."Combination Attack".
Speaking of Den-O, there's the scene in Kabuto's world where Tsukasa puts the Taros' Attack Ride cards to use:
Decade:Ore, sanjou!note I'm here
Decade:Then how about this? *changes to Gun Form* Can't hear your answer!
Gatack:But you didn't ask us anything...
To add up to the awkward feel of the scene, the Decadriver repeats each Taros' catchphrase in a heavily English-accented Japanese.
In the World of Hibiki, Kiva-la decides to summon Ouja to release a very large sized Bakegani. Unfortunately for Kiva-la, she proceeds to get hit by Ouja's kanabo right into the TV screen.
Mind you, this Ouja is not the AR Ouja, but the original Ouja (in other words, Asakura himself)...
In episode 28, Amazon is getting his ass kicked...
Tsukasa: "Ah." *Holds up baseball instead of change card, complete with revving sound effect.*
Den-O: *kicks Mook out of the way* Stop interupting me, you bastard! Ore, sanjou! Man I'm the coolest.
The net spinoff videos. All of them. Decade gives henshin pose lessons, Narutaki obsesses over butts, and even the actors themselves have a hard time maintaining character in the face of the crazy goings-on.
Also in Hyper Battle DVD: Protect! The World of Televikun. Tsukasa, Yusuke, and Kaito fight over for the magazine and accidentally dropping Natsumi's cakes. Kaito immediately accused Tsukasa and Yusuke, who dropped the cakes. Natsumi find out that Kaito himself dropped the caked, and directly using her signature Secret Laughing Pressure Point to Kaito. Then she talks to the audience...
Natsumi: "Blaming someone else is the worst thing you can do."