Being the guy who appears on Forbes' "richest people in the world" list at the very top... only later to be revealed as a huge scandal because, well, my net worth is really very low.
Then I would get rich from hitting the talk show circuit as the poorest man ever to be the richest man.
EDIT:
I just realized my idea was too similar to SouthernN'Proud's. How about the fifth guy to walk on Mars? I get the experience of flying through space, walking on another planet, but none of the media attention that the first few guys to walk on Mars would be inundated with.