Hey, I got an idea!!!
How about say, you get to the very late stage in the game and an advance triggers alien contact? Say the SETI program, and the first nation to build the wonder automatically gets an allience with an alien nation that is on another map (but it would be like TOT on a space map), and then aliens would randomly visit other civs, but the alien nation can't start attacking until it has made contact with all civs.
Just say that no one knows if the SETI program has been built until they either build it themselved or get visited by aliens. At this stage of the game the barbarians could just dissapear and be replaced by the alien nation which the leader has its own diplomacy screen and everything!!! Or at that stage of the game the alien nation could even be played by a human!
That would be wicked!
Oh, and I got another idea! The alien nation could just be a mirror image of the earth nation all rolled up to one (on a seperate map), so the only real way to avoid the end of the world is to ally with each other and have total world peace to kill the alien nation!!!
This is the best thaught I have had all my life!!!
MrLeN
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Where there is money, there are liars!