I say this in all seriousness:  I, Thomas J. Happ, have found the cure for cancer.  Or at least an exact copy of me did.

I did this using a quantum random number generator.  For anyone who doesn't know, these work by generating numbers on a quantum level.  The numbers are guaranteed to be absolutely random.  As such, whenever you generate a quantum random number, (say 1 - 10), what's actually happened is you've split the universe into 10 duplicates of your own that differ only by this number (or, if you subscribe to the multiple worlds theory of quantum mechanics, 10 worlds were just removed from quantum superposition, but they technically are part of the same universe).

I used the random number generator to make several binary files filled with random numbers, then ran them as programs.  Although it shouldn't matter, I did this under both Windows and Solaris.  The largest of my files I generated overnight and was a gigabyte in size - overkill, to be sure, but creating a large number of duplicate universes - 8,589,934,592, to be exact.  In each of these universes a completely separate program was generated.  In most, they didn't run, but in some, a cure for cancer was found.

In these, it so happened that the randomly generated binary corresponded to a fully functioning executable.  Much to my surprise, on running the executable Adobe's Acrobat Reader automatically opened up to show a me a PDF containing a scientific paper detailing this cure.  Simultaneously a window appeared informing me that this paper had been automatically e-mailed to the world's leading researchers, withholding the bit about it being randomly generated, and that I would have to do nothing more for my cure to eventually make its way into medical practice.

Of course the nigh miraculous nature of computer programs ensures that I simultaneously cured several other diseases, possibly even death itself.  Basically any possible scientific discovery that could be made was, in the proper universe.  I would be unsurprised to learn that in some of the universes my program turned out to house an artificial intelligence, or multiple intelligences.  If my laptop couldn't house such an intelligence, perhaps a randomly generated hacking program could have created a self-propagating virus that would subvert other machines and use each of them to connect to the quantum random number generator and create a networked intelligence in tandem.

Indeed, my act was not all a kindness.  In some universes I may have birthed a Terminator-esque "Skynet".  I'm still not sure how I feel about this, though my general feeling is that throughout creation there is a greater tendency towards helpfulness and compassion than otherwise, and that in these 8 billion universes much more good was done than evil.

Of course, you may be asking, what result did I get in the universe where this article was written?  I'm sad to say that my programs did not run - as far as I can tell, anyway - a sophisticated enough program would be able to mimic the OS and fool me into thinking nothing happened.

If you are interested in trying this experiment for yourself, you can find the necessary executables on http://random.irb.hr/.  Please think for a second before doing so - you truly are dooming the planet in several different universes (or maybe just landing yourself in jail), even if you save it in several others.