I just saw here on reddit the behind the scenes of the hospital explosion in "The Dark Knight" and these always truly fascinate me. (The behind the scenes not hospital explosions)
I've of course seen the Tom Cruise Mission Impossible stuff but I want to see more of it. It doesn't "ruin the magic" if anything it makes me appreciate it more.
Sure back in the day they had some of this in the bonus features on DVD's and Blu-Rays but let's be honest thats not how the average person watches their movies now.
It would just be neat to get an opportunity to see all the hard work that goes on to provide us with the best experience.