What's that you say? Well, it's a rather new and impressive tool which allows you, the avid half-life player, to talk to people on IRC whilst playing the game! The HalfIRC web site explains how to use the program, and also states the download links which are currently available. Here's some more information about it:
HalfIRC is a new enhancement to the popular Half-Life 3d engine, allowing you to monitor your favorite IRC channel from within the game, even enabling you to talk back without hassles. Toggling the chat display is as easy as pressing one key, issuing IRC commands is as simple as chatting with other players on the server.Of course, we at CS-Nation have our very own mirror for your downloading needs, so don't delay and download HalfIRC from us here. Alternatively, visit the HalfIRC website (all German mirrors).