Here (via Movieline) is a video that provides concrete proof that The Simpsons predicted 9/11 in 1997. The video goes on to suggest (jump to 6:17 to skip all the arduous Lone Gunmen stuff) that The Simpsons also predicted a huge false flag nuclear attack on an American city on November 6th, 2010.

Oh my God! Everyone clear out of American cities by November 6th! The Simpsons has proven that, without a doubt, there will be a nuclear attack on November 6th! There's no time to...oh.

Never mind.