There's some controversy on dress code in schools, but at least hair has been pretty free. I had purple highlights for a while in high school, and my friend dyed her hair blue. Back when I was a freshman/sophomore, there was a punk group of the nicest guys. They would dye their hair bright colors and shave pictures into their heads. My favorite was this one guy who, for Christmas, dyed his spiky mohawk red and green, and put little santa hats on the ends