I used to think that they were just a fashion statement in dance class... but no... they actually keep your calf muscles warm during exercise so that you don't pull or strain them so easily. I fell in love with a pair at payless for five bucks last December... I almost walked away from them since I hardly every make off the cuff purchases, but my sisters persuaded me, and I haven't been sorry since! One of those random purchases that you are so happy with afterwards =)
Thanks to my sister for the lovely photo...