It’s temporary, it’s original, and it's a fly summer style that can transition into fall. Even better, you probably learned how to do it during summer camp: tie-dye your hair, why don't you?
Pictured is a woman in the Haight Ashbury who used blue and purple dye. For fall, you can use darker tones like rust or burgundy.
First, highlight the tips of the hair using hair bleach. Don’t fret, if you use the correct amount of bleach, you won’t damage your hair. Fold the hair into a piece of foil to let the bleach process. After shampooing and conditioning the hair, blow-dry -- if it's wet it will absorb less color. Then, using whatever hair dye you chose (blue, teal, pink, purple, etc.) begin painting the tips of the hair with a color brush. Using a brush will help the colors blend together.
For more details check The Beauty Department's gorgeous pictorial how-to