Sounds like a good project Carol! Did you have a material in mind that you'd like to try?
++A family member did hers with tongue and groove wood, lightly stained in a pale blue. It is gorgeous!
I love bead board ceilings.
Bead board or tongue and groove cedar would look really nice
You could also tent the ceiling with heavy canvas or parachute fabric and do a border around the top of the wall.