Here's some speculation that definitely came from the House of Crackpot Theories, but since it's kind of a slow day with the holiday today, feel free to let your imagination run wild. This video suggests that the next iPod touch could use its internal gyroscope and the Facetime camera for a sort of psuedo glasses-free 3D. Icons on the home screen could tilt and shift according to how you're looking at the phone, and games could bend and shift around as you move the phone and your own head in the camera.
It's highly unlikely that we'll ever see this in the official iOS, however. Nintendo is set to release