Bill Zeman is an illustrator whose very cute blog operates on a simple concept: His 4-year-old daughter tells him what to draw, he draws it, and she critiques it. He's been doing it since she was two. Some samples:

X-Ray T-Rex

The Brief: A dinosaur in a X-Ray
The Critique: I just want to see a little mousey in his tummy
Job Status: Approved (after addition of mousey)
Additional Comments: That's what kind of bones dogs like to chew on. Dinosaur leg bones.

Bone Dinosaur Eating a Baby

The Brief: A bone dinosaur eating a little baby
The Critique: No! A baby dinosaur!
Job Status: Rejected
Additional Comments: He's just going to be nice to that baby he's got in his mouth

Much, much more here.