Winter isn't over yet, folks, so you need to keep thinking about staying warm out there. That doesn't have to mean you don't get to have convenient portable music. Nike has just announced their unfortunately named Hatphones, which are, you guessed it, a hat with built in headphones. In addition to the headphones, it's got a pocket in the back for your iPod nano (with Nike+ sport kit, of course). The pocket has a "power mesh window" that lets you control the iPod, although I don't really get how you control an iPod that's stuck to the back of your head.
In any case, this is a nice option for people who think wearing regular headphones under hats are uncomfortable. Beware, however, as it's a tad bit pricey at $60.