Newsweek has published a list of what it believes are conspiracy theories. Among them, naturally, is the belief that "9/11 was an inside job":

12. 9/11 was an inside job.
The truthers, holdovers from the Bush days, just won't go away. They argue that the physics of the World Trade Center collapse doesn't add up, and that the attacks were an excuse for the U.S. to launch wars abroad and enrich defense contractors. Either the government planned and executed them or it knew they were coming and turned a blind eye.
Proponents:Alex Jones, retired religion professor David Ray Griffin, Reagan administration policy analyst Barbara Honegger, British journalist Robert Fisk.
Kernel of Truth? Not even the staunchest mainstream George W. Bush bashers believe this one. Enough said.