I have noticed a trend happening with curtains and it is to paint them, not just any color but more often they are....BLUE! I have found two good examples of how to transform a curtain with paint.
|image from: Apartment Therapy|
This Patterned curtain is done using stencils and left over latex paint to match the current wall colors.
|image from: la vie en rose|
On this over sized curtain they did Ombre Stripes using masking tape and paint.