Ok, since I called this "looney," I have to do some on the two people called "looney" in the book: Lupin and Luna Lovegood.

There once was a werewolf called Remus J,
Who (though a werewolf) was quite OK,
He loved his work,
He didn't shirk,
But couldn't get jobs which would pay.

There once was a student called Luna,
Why wasn't she introduced soona,
She might love Harry,
Now THAT would be scarry,
But there's more than we think to Luna.

(I do belive she will play a bigger part in the next books. But I don't think Harry/Luna. I read in an interview with JK that she already knew who Harry would go with, and she'd dropped clews to that in previouse books. SHe also said that it wasn't as easy as all of us thought, and she'd be annoyed if we figured it out, considering that it took her considerable effert so that it would come to us all as a surprise. THat seems to rule out most of the people thought of)

(In answer to noseinabook: Yes, ab stuff refers to the rhythm, but also the rhime.)