In the June 2008 issue of Southern Living is an interesting idea for partially enclosing a porch; the home owner bought two small French doors at a home improvement store and installed them on the side between a column and the house and then a larger French door at the front and attached it to the corner column; she had to add extra trim to make them fit and more trim for looks and then painted the wood. It looks beautiful.
Another interesting idea is decorating sloped ceilings with murals or decals. I think that glowing stars would be fun too or stencilling. And in an outdoor kitchen, the ceiling was enhanced with strips of bamboo.
Btw, here's an idea for making your garden more interesting at night. Get one or more of those solar-powered lights that change color. I have a sphere in my front garden (I got it for Christmas from Gardener's Supply Co.) that I enjoy looking at from the house or the porch or walking out to the garden. A neighbor noticed it the other night and enjoyed watching the colors change. (Red to green to blue). I've seen a similar idea in another gardening catalog recently.