David Icke is the nuttiest of nutty conspiracy theorists. He believes there is a colony of shapeshifting lizardmen on the darkside of the moon. I think he is genuinely nuts. The true example of the farthest that conspiracy nuts can go.
http://www.youtube.com/watch?v=1w2dMekIJLw
http://www.youtube.com/watch?v=1w2dMekIJLw