I bought an iPod nano from the apple store about 2 weeks ago, and noticed today that when moving my finger along the clickweel I could sometimes feel a popping/clicking motion. I figured out that what I was feeling was the center button rotating: when I put my index finger on the center button (alone) and rotate, I can move the button ~45 degrees left and right before it hits something and stops rotating. Is this normal behavior for a nano, or has something broken underneath the button?