It’s a ball. It’s a hair accessory (correction, many hair accessories). It’s both! These colorful balls—made up of 100+ elastic bands each —are popping up everywhere I surf (www.hatattack.com, www.bumbleandbumble.com, www.hottopic.com, www.jcrew.com, to name a few). They’re fun, bouncy and, best of all, practical. One will last a year, easy. And they make great holiday gifts—for pretty much anyone on your list with, um, hair….