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: 
	* DNS queries 
	* Babelfish translation 
	* Google searching 
	* Excuse generation 
	* Insult generation 
	* Karma 
	* Per-channel quote storage, searching and retrieval 
	* Reminders 
	* rot13 translation 
	* Check the spelling of a word 
	* Webserver Server: header examination 
	* RPG dice rolling (thanks to David Dorward) 
   * Multi-language support - comes with english definition only so far

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