I don't know how common this is, since I don't watch much HDTV aside from sporting events. But last night, I was watching some of the last bit of Mission Impossible 2 on CBS HD. It was in full HD mode, with the right aspect ratio and everything, so of course it looked stunning. But then--in the middle of a scene, no less!--it switched to modified aspect ratio, and back down to the non-completely HD signal (I'm sure there's a better term for that, which I'm not familiar with). Anybody know what happened with that?