rbot is a ruby IRC bot. Think of him as a ruby infobot, with more and different 
features, and a nicer plugin scheme. His main features include:

    * Runtime configuration via irc chat
    * User authentication and access levels for using different bot features
    * Built in infobot-style keywords. See example session below.
    * Support for underlying fact database (infobot fact files), which can be 
      overridden or supplemented by runtime keyword controls
    * Powerful plugin architecture, comes with plugins for:
          o DNS queries
          o Babelfish translation
          o Google searching
          o Excuse generation
          o Insult generation
          o Karma
          o Checking the weather
          o Querying slashdot
          o Doing Math
          o Per-channel quote storage, searching and retrieval
          o Reminders
          o rot13 translation
          o Check the spelling of a word
          o Webserver Server: header examination
          o RPG dice rolling (thanks to David Dorward)
          o Slapping people :)
          o larting people
          o conversation stats
          o more...
    * Multi-language support - comes with english definition only so far - 
      translations welcome

WWW: http://linuxbrit.co.uk/rbot/