Star Trek once brought up a very good topic for their show. They proposed that a group of advanced aliens came to Earth thousands of years ago and made themselves gods in the eyes of the people. At one point, Captain Kirk meets up with Apollo (sp?). Stargate tv series also uses this concept.
Actually, I wouldn't be surprised if we actually do find evidence that the various deities of the past and present are a result of Alien visitation in our distant past.
Hate world.
Revenge soon!