I have thought of this post many times since it started a few weeks ago. My DS 3.5 has a new obsession: writing/making books/spelling. It's ALL DAY. He does this for an hour before preschool, then at preschool, then for hours at home. Just spelling, spelling, spelling, writing and making these little books. It's been about 5 days now. And when he's not sitting down doing the writing, he's spelling outloud. I have a feeling that when he feels this is mastered, it will settle down.