sim (simple instant messaging) is an IRC client specialized for use with bitlbee. It is based on sic (http://suckless.org). It reads commands from standard input and prints all server output to standard output. It also multiplexes all channel traffic into one output, so you don't have to switch to different channel buffers. sim must be customized by editing its source code to insert the correct username, server, password, and identification information.
DutchPIPE allows Web developers to make virtual multi-user "avatar" environments. Each Web page becomes an abstracted environment or location where visitors and other items on the page are visualized. This status is retained as visitors move around. A lot of real-time interaction is possible, resulting in persistent interactive page environments. DutchPIPE uses AJAX and the DOM for the browser, and it works without Java, Flash, plugins, or firewall adjustments.
Twisted Words provides implementations of a handful of IM protocols, including IRC, MSNP8, OSCAR, TOC, and Jabber. It also comes with a multi-protocol server built around a few simple interfaces, the goal of which is to facilitate implementations of novel servers, clients, and bots. Out of the box, it comes with server that accepts connections over IRC and PB and seeks out installed third-party plugins to support other interfaces (for example, a Nevow LivePage-based Web interface).
antioch is a Web application for building scalable, interactive virtual worlds. Begun as a MOO-like system for building virtual worlds, the goal was to take the LambdaMOO approach to creating online worlds, and update it in hopes of attracting new players to an old idea. Like many MOO clones before it, antioch uses Python as its internal scripting language. This provides a powerful environment for game authors, while a flexible object model allows for creation of complex in-game objects.
Lisppaste is a fully-featured pastebot that provides a Web interface to submit pastes, and announces the URL the paste is stored at to a channel of your choice. It features multiple channel support, paste annotation support, persistent pastes, a Web interface to the list of pastes in the system, RSS support in short and full varieties, XML-RPC support, and direct linking to meme IRC logs.