AliceBot is an artificial intelligence chatter bot that uses AIML (Artificial Intelligence Markup Language) There are many different versions and scripts out there.
Talk to Alice http://www.pandorabots.com/pandora/talk?botid=f5d922d97e345aa1
AliceBot and AIML downloads:
http://alice.sunlitsurf.com/downloads/
Alice.tcl scripts to work with eggdrop bots: http://tcl.moshtech.com/cgi-bin/dbs.cgi and search for "alice"
A provider for bots for people who want a bot quick without needing to setup their own server