I have been on the hunt for some bookshelves for our girls' room that are wall-mounted and display the fronts of their books. Thanks to this blog (that graciously awarded me some prizes recently), I discovered that you can use rain gutters to make front-facing bookshelves! The tutorial is here.
I looked into it a little further and it looks like the cost is about $3 per 10 linear feet! Can't beat that. I think this project is perfect for a play room or nursery. Check out a few of the google images results: