I saw someone walking down the street with a headband similar to this, and decided to make one for myself. The pattern is pretty simple, don't be put off by the single cable. I posted a picture tutorial for cabling under my last headband pattern, which you can find here. The knit 1 purl 1 ribbing on this piece makes it a bit thicker, and helps keep it flat instead of curling at the edges. Hope you enjoy the pattern!
Worsted weight yarn
Size 8 (5mm) needles, and a spare needle
Cast on 20 stitches
Work knit 1 purl 1 ribbing until half the length of the diameter of your head (approx. 9").
Put the first 10 stitches on a spare needle and hold them to the front of your work. K1 P1 to end of the row. Put the first 10 stitches back onto the needle, and then K1 P1 to end of row.
Work knit 1 purl 1 ribbing until desired length. Cast off stitches, and sew the two ends together, and weave in yarns ends.