Since 1947, both the public and the media have been fascinated with flying saucers, floating triangles, odd lights zooming across the sky, and the little gray or green men thought to pilot them. And while it's not completely out of the realm of possibility that we may have been visited by an alien civilization, the odds that it happened, much less that it's happening all the time, are beyond overwhelmingly against it. So why are we seeing so many strange lights in the sky and hearing so many bizarre stories about them and their supposed pilots?