Revealing mistake: In the David Letterman scenes, Paul Schaeffer's head is shaved, which he just did recently (maybe within the last year to year and a half). (01:15:00)
Revealing mistake: When Homer placed the rocket on his fence and lit it his friend asked "Should we get behind somethin'?" That's when the rocket explodes. When you see them fly back you don't need to slow motion it because you can clearly see the wires attached to their backs.
Revealing mistake: The same extras can be seen in several different crowd scenes. Specifically, the same people can be seen in the crowd that storms the computer fair and in the auditorium when Steve Jobs makes his final speech.