The post below may have been trivial, but this is serious stuff. This BYU prof argues that the way the buildings collapsed on 9-11 is much more explicable in terms of physics if one presumes that the collapse was caused by explosives, not by crashing airplanes.
I know, it sounds crazy to me, too, and I've dismissed most of this kind of stuff out of hand. But while I don't have the physics to evaluate the merits of this guy's position, his fundamental point seems hard to argue with: The theory that explosives caused the collapses is testable and falsifiable, so why not test it? He calls for the release of 6,899 photographs and more than 300 hours of video footage for review by an international, cross-disciplinary research team that would consider all options.
To his credit, he avoids speculation about who would have planted any such explosives or why.
UPDATE: Here's one pretty thorough argument against his theory. Other responses I read fell predictably into liberal and conservative camps. Why a purely scientific question should become a political football illustrates pretty well how poisonous the national climate for debate is.