The sensor is not recognizing my movements!
If the sensor isn't recognizing your gestures, try calibrating it using the included Kinect Sensor Calibration Card. Open the Kinect Guide, then select Kinect Tuner. From there, run sensor calibration with the included calibration card. Keep the card for future use.
Don't forget to turn off controller mode if you've been using the controller to navigate the menus and now want to use gestures again! If you've got controller mode on, there should be a small bar at the bottom of the screen telling you to press "Start" to turn off controller mode.