Conspiracies

So I'm currently in a study period at school. Theres a gifted and talented lesson going on behind me, about conspiracie theories.
I LOVE CONSPIRACY THEORIES. :]

I did my speech this year on the moon landing, how it didn't actually happen and what not, and it was probably the most fun I'd ever had writing a speech.

I found this awesome site that had heaps of conspiracy theories. Things like Paul McCartney died 10 years before the Beatles started, so they had a look-a-like fill in for him, and 9/11 was set up by America as a reason to go to war.

Anyway, my question is, what versions of conspiracies have you heard?