I first started noticing this look on the always fashionable Serena van der Woodsen on Gossip Girl (one of my favourite shows, hello Chuck Bass).
I also like the way Nicole Richie wears a scarf, over the top of her forehead. It's a hippie inspired look, adding a carefree vibe and ease to her look. She chooses bright and playful prints to add a pop to her neutral attire and finishes the look with a pair of stylish shades.
Another way to wear the headscarf that I really like is to spin it around so the knot or bow is on the front!