Reminds me of the turing test (which is very topical)
Have you poked around at the transcripts from the turing tests?
Fun - they come so close, then this happens:
bot: "I like to chat with my friends, what do you like to do?"
me: "martial arts"
bot: "ouch, that hurts, don't press the keys so hard!"
me: "cute - thats actually a clever response"
bot: "Now the real truth comes out. Go on"
[splat]
Thats an actual transcript.
http://www.surrey.ac.uk/dwrc/loebner/