OpenVerse is similar to other graphical chat systems like Excite Chat and Microsoft Chat, with the main differences being that OpenVerse is open source software, has no advertisements, and also runs on a variety of systems including Windows, Unix, Macintosh, and just about anything else for which you can find a copy of TCL/TK.
Perlbot is an IRC bot written in Perl. It depends on Net::IRC and its goals are simplicity and modularity. The base bot allows auto-opping, notes, multiple channels, etc., but much much more is possible through the use of plugins. Many plugins are included, and it should be easy for anyone with some knowledge of Perl to write her own.
PhpWiki is a WikiWikiWeb clone written in PHP. A Wiki is a Web site where anyone can edit or create the pages through the Web browser, with no authentication. PhpWiki works right out of the box with zero configuration, and comes with a set of default pages. It's useful for collaborating on documentation on a project, having freeform discussions, and easy editing and searching.
Praya is a window to all your messages. It ships with many protocols, including DICT, IRC, gale, Maildir, a timer, and Yahoo! Pager. Praya is easily extendible. Adding new protocols is relatively straightforward. It has a modular architecture which makes it easy to write bots, gateways, spam filters, etc.
The PTlink IRC daemon integrates some of the most advanced features needed to manage an IRC network into the stable core from Hybrid IRCd. It is fully integrated with PTlink IRC Services and PTlink Open Proxy Monitor, providing a great platform for anyone starting an IRC network.