I decided to clean the kids' room without their help this morning. :) Shortly after I was finished, my 4-yr. old entered the room, and started making the beds.
I never make their beds. Their bedding consists of a fitted sheet, a pillow with case, and a blanket thrown on the bed. We don't have any special or matching comforters, so I've never been big on making their beds. In fact, I've never even taught them how to make their beds.
It must be instinct. :)