Kodomo no Omocha (or Child's Toy) is a 10 book series about the insane child actress, Sana, and her life. The anime series follows the manga very closely up until episode 20 or something, so until that point, it's pretty much like the anime except not as hyper. After that, it kind of goes off on serious, shoujo tangents.
Manga Manga Manga!
Kodomo no Omocha is © Obana Miho