Another "Common Truth" that has just kept gathering steam through pop culture over the years till one day people will think its true because they don't remeber the actual event any more.
Most recent occurrence for me was a Sci-Fi video game called "Area 51." The main character (voiced by David Duchovny aka Mulder of X-Files) is fighting off aliens and whatnot. He comes along an area where they have a fake moon landing studio setup and a prerecorded script over the speaker system. I think it was more to poke fun at the conspiracy theorists then to say it happened, but there it was nonetheless.
The same will probably happen to 9/11. In 30 or 40 years if the media has their way, Bush will be the one who committed 9/11.
"Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery.” – Winston Churchill
"Your eyes can deceive you, don't trust them." - Obiwan Kenobi