The movie JFK opened my eyes to the nutty world of JFK assassination conspiracists. Funny thing is that most of their theories are crackpot or just plain wrong.
A critical flaw of the theories is that they require a massive and perfectly executed covert operation that was kept perfectly secret for 40 years. Only a complete nut job could believe that the United States government is capable of this.
I believe that the Warren Commission’s report is likely as correct as we’ll ever get.
http://mcadams.posc.mu.edu/home.htm does a great job at debunking all the JFK nutzo theorists.