I used to play CTP all the time on Deity, and would usually win...

but there was this one time I was playing against 4 major civilizationsb (rest were dead) and I was the americans, and the others were Persians, Greeks, Minoans, and Chinese. It was fairly late in the game, I had maxed out tech, and lots of good cities, so I decide to go for the alien works way out of the game... and I build all the stuff, only to see that the Persians start to build theirs too... and it gets up at an alarming rate.... faster than mine!

So I go over and bomb the hell outta them, so they can't build it...

but the moral of the story is don't count out the AI, the second you think they won't do something, they will....

May not be the smartest AI, but it will fight back if you do somethign to it