I wrote a Markov Chain HN comment generator a few months ago. I'd say a solid 70% of them were pretty funny.
there seems to be a market coming soon for such software - on one side government and politicians need to push their propaganda domestically and internationally through web2.0 and social media channels, on the other side ordinary people may soon want to have artificial realistic chatter generation tools as a way to increase chances of preserving privacy of their communications.