We read the first two chapters of Grammar Land today on our new Kindle. 
It was great! My ds9 loved it and has been playing Grammar Land for the past two hours since we read it. He is Dr. Verb, he says. My ds11 is Mr. Noun. My dd6, who did not even hear the book, is Adjective. He even drew a picture of Grammar Land and how he thought it would look. At one point he looked and me and asked what kind of words dd6 had since she was Adjective. I said, “adjectives decribe nouns,” and he nodded his head and as he ran out of the room I heard him say “Ajective tells about nouns.”
They are calling me Mrs. Judge Grammar and are saying that dh is Judge Grammar himself but he is out on errands at the moment. 
Gotta love it.