Tutorial for easy DIY knot headbands. Cute, simple look. There's also a quick tutorial near the bottom of the post about making one of these out of a non-stretchy fabric, sewing part of headband to be more elastic-like.
I used to do this to my girls' jeans after school let out. Great way to boost the summer wardrobe for next to nothing! Transform an old pair of jeans into adorable summer shorts using bias tape. Instructions on the site.