Funny, the most attractive pseudohistories to intellectuals, such as "The Origin of Consciousness in the Breakdown of the Bicameral Mind" and it's novelization "Snow Crash" and the most attractive to non-intellectuals, such as "Holy Grail, Holy Blood" and it's novelization "The DaVinci Code" don't have terribly large implications. (well, the real history part, about Christianity having a history, does, but not the rest.)

Aliens are generally very boring IMHO, as I don't even feel that they make predictions.