We're in the process of creating DD's playroom (woodland creature themed) - we went with an avacado-ish green (Valspar Organic Garden I think...) above the chair rail and on the ceiling, and a brown (Valspar Chocolate Truffle) below it. The bottom portion of the wall was primed with magnetic primer (3-4 coats) and we followed the Martha Stewart instructions for DIY chalkboard paint to top it off.
We turned one of the two closets into a reading nook (toybox/bench to sit on, shelves above to the ceiling, and DH built a pergola that comes off the top of what was the door frame. I bought some realistic looking branches/vines from Hobby Lobby and kinda wrapped them around/through the pergola. I'm using a vintage flat sheet in a floral print to make a curtain that she will be able to pull to the side or close.
I also painted a wall mural tree on one wall (and plan to find floating shelves to attach to a few of the branches). There's hedgehogs, mushrooms, squirrels, and birds/owls... I have a collection of different sized birdhouses that I am painting and will either put them on the floating shelves or hang the collection of them together with microfilament in one corner of the room.
I love the look of these shelves from etsy http://www.etsy.com/shop/TheWoodenOwl