Yeah, it never fails to amaze me. On one hand, these guys are such geniuses that NOONE BUT AN ENLIGHTENED FEW EVER SUSPECT THE TRUTH, and on the other, they continually screw up.
Here's an ugly little joke I recently read:
"How do you know the CIA wasn't involved in the JFK assassination?"
"He's dead, isn't he?"
But my favorite fantasy is the idea that the 9/11 hijackers were some sort of criminal masterminds, and/or ninjas. They were a bunch of mean little creeps with a little knowledge and a fair amount of willingness.
Personally, I think the reason people jack up these bizarre theories lies in the fact that they don't want to face reality. It's hard to accept the fact that we live in an extraordinarily-complex, technologically-sophisticated but oddly delicate world--and in such a world, the fact is, anybody who's willing and has three brain cells to rub together can do a considerable amount of damage.
I also think that this particular set of conspiracy fantasies has some quite ugly roots in anti-Semitism and what Edward Said identified as Orientalism. You know--at home, it's the Insidious Trilateral Commission and the International Monetary Fund, and abroad it's whatever version of the Insidious Dr. Fu Manchu we believe in at the moment.
On the other hand, at least it's entertaining. In the same vein as the last poster, I truly enjoyed the website explanations that argued that because the Us Air Force had been working on pilotless drones, the planes that flew into the Trade Center must have been remote controlled. Among their backup evidence was the repeated mention that this plane or that plane WAS ONLY 27% FILLED!!!
Fact is, the people from the future did it. See the movie, "Millenium."