http://www.jfkreloaded.com/
Seems that it puts you in the position of Lee Harvey Oswald. You must shoot JFK in the manner described in the Warren Report, thus showing that Oswald had the means and opportunity to have been the lone gunman.
To enter the comp, you have to pay $10, which gives you some tokens to spend on entering.
Interesting concept for a video game...
(Downloading it now, will let you know what it is like).