hair bands

Hair bands. Doesn't that generally conjure up images of girls attending junior primary school or perhaps ladies in the gym doing a body attack class? Catching public transport to work each day has given me the chance to observe a whole assortment of different people, including at least 3 guys last week who were all wearing hair bands! Since when has it been fashionable for guys to be wearing them, and I'm not talking bandanas! Did I miss the memo? Can someone enlighten me to this new phenomena?