Eggdrop is an IRC robot, designed to be extended by Tcl/Tk..
Scripts for eggdrop bots are written in Tcl, extended by the addition of many eggdrop-specific commands that are described in tcl-commands.doc that is distributed with eggdrop.
This is a page of links for those who write eggdrop bot scripts. Please feel free to add good quality links to pages that deal with scripting techniques in this area.