Over at the Ace of Spades the old "no plane hit the Pentagon" moonbat theory has enjoyed a brief revival, if only as a punching bag for Ace (update: Ace hat tips Secure Liberty for the info). If you want to see the video that spun Ace (and others) up, you have to go to the links above because I'm not going to give the dishonest cretin who spawned it any more links than he already has. Apparently this piece of fiction was "inspired" by a piece of French writing (L'Effroyable Imposture or "The Frightening Fraud") by some goober named Thierry Meyssan who probably also believes the moon landing was a fake.
Snopes.com effectively disassembles the whole "conspiracy" here.
The trouble is that there are people out there who are all too willing to believe such tripe. That's truly frightening.