[Edit]
It's an extended version of the Naruto Gakuen ending during Shippuuden. It has the voices of the original characters, mostly narrated by the girls after the first part. It starts at the climax of a fight between Sasuke and Naruto, then goes back to start at the beginning.
It's done in manga format, with the characters explaining what's going on in the background.

And it's absolutely hysterical.