What about the other senses?
As I was doing some work on my HT setup this past weekend, I was thinking about what else could be added that would go beyond sight & sound - after all, we have more senses. While adding olfactory effects would probably not be my first choice, I have considered butt-kickers (Amazon link), but always thought they were a little tacky.
So what else exists on the bleeding edge of uber-expensive HT setups? I could imagine climate altering effects - when you're watching a scene in the snow it would get cold in the room, or wind effects with hidden fans, for example. Of course this would have to be encoded on the disk, or maybe it could be deduced from it? Anyhow, just wondering what's out there...