rubIRC is an IRC client, written and scriptable in Ruby. It runs on Linux (GTK+) and Windows (FOX).
rubIRC was written specifically for scripters. Its philosophy is that a scripting environment is only sufficiently powerful when the client itself can be written in it. To this end, rubIRC is divided into some basic components upon which the main
script runs.
Note that I haven't worked on rubIRC since 2001, so it may not even run!