One of my very favorite things I have made and even mention in my profile is a valance for my daughter's window.
My great-grandmother made this absolutely perfect floral pillowcase with a ruffle and a bit of trim (like seam binding) along the edge and made into a bow.
After much debate with myself, I decided folded up in drawer was just silly and not what my great-grandmother would have wanted, so I very carefully ripped out the seams so it was a flat rectangle of fabric (with a ruffle, of course!). I made a lining for it with an opening at the top of the sides to thread the curtain rod through.
I found a discounted rod at PBK, glued some sparkly cupboard knobs to the ends, dug through my closets and came up with some sheer ribbon to tie the fabric up and turn it into a sweet, girly-girl valance!