Cracking your knuckles doesn't cause arthritis, a man won a Nobel for cracking one hand and not the other and proving it.
There were designs for a computer one hundred years before the first computer was released, but because of lack of funding and political interest, it was never made. We're one hundred years behind technologically because of it.
Peter Parker was very nearly molested as a child, the story was told after he heard his neighbor being molested by his babysitter and went over as Spider-man to tell the kid how he told his aunt before the creepy old man took it any further.
Iron Man currently has a suit that acts like a technological version of Carnage. Thinking of it in terms most people would understand, Carnage is the bad Terminator from T2, the liquid-metal one, and Iron Man is the Terminator from T3, shapeshifting to make energy projectile weapons along with the blades. Anyone who reads the book and read Iron Man/Thor on free comic book day would know this, but it still makes me happy.
Super Hero Squad was in the works before Disney bought Marvel. Would everyone stop bitching about Disney ruining Marvel with it, because I've actually seen nothing but positives with the whole ordeal.
That's all I can think of right now. I'm sure you didn't know at least one of those things.