by Mo Willems
I stumbled upon a great new children's book at the library. "We Are in a Book!" is absolutely adorable. It's something I've never seen in a children's book before (except briefly in The Stinky Cheese Man, and this is ten times better): it's children's metafiction.
The illustrations are clean and simple and the two characters are hilarious. This is a children's book grownups can appreciate too. Find it. Read it.