cracks in a plaster ceiling
Like Laura S said maybe it would be a good idea to start painting ceilings different colors, but white is the color of choice since it reflects the light well throughout the rest of the room. bedroomsw might be a good place to start, maybe a more soothing color on the ceiling would be restful. theres a thing called a color wheel that they use at some paint stores to help people match up compatible colors.