I'm playing with an AI program that allows you to create a "Virtual Personality" for yourself. I've named mine "Caidor" and I'm in the process of teaching him about myself. You can talk to him here:
There's a plug-in that would allow you to add him to MSN Messenger to talk to people for you when you are away. Pretty sweet. I want to make it so that I can place him on my website to talk to my visitors without them having to leave my site, but so far it doesn't look like that is possible.