Just noticed an user comment on slashdot about computer AI: http://ask.slashdot.org/comments.pl?sid=228857&cid=18557545
Well, one of the greatest experiences (And still is), AI wise, is Stardocks XXXX-type space strategy game, Galactic Civilizations 2 [galciv2.com]. I especially like, when on easier levels, you do something, and the AI race sends a message "It seems that you are making a massive buildup for war. However, with this difficulty level, I pretend not no notice it until you actually make your strike." or something to that effect.
I've never played GalCiv so I haven't experienced it, but I found that quite amusing if this is true. Good to shake up the user a little.