Does he have an iPod? If so, I'd get him an iTunes gift card. They're versatile (because they allow the recipient to choose exactly what music or apps he or she may want), they're easy to wrap, they don't require parental transportation to the store/mall, and they're definitely not "childish" in any way. Also, you can pretty much spend as much or as little as you want on one, because they come in a variety of denominations.