Whimsical headpieces were a hit this winter but since we live in the real world and not on the runways, we need a way to tone it down but still show off our playful side     Diane von Furstenberg had fun with her headgear this fall. Her bright and cheerful pom pom hats were an adorable addition to her Fall/Winter 2009 collection.     Forever 21's yarn pom pom hair elastics are our choice for fun and childlike headgear. And at less than $3 a pop, how can we go wrong?