Wikipedia
MIRC
mIRC is an Internet Relay Chat (IRC) client for Windows, created in 1995 and developed by Khaled Mardam-Bey. Although it is a fully functional chat utility, its integrated scripting language makes it extensible and versatile.
mIRC has been described as "one of the most popular IRC clients available for Windows." It has been downloaded over 40 million times from CNET's Download.com service. In 2003, Nielsen/NetRatings ranked mIRC among the top ten most popular Internet applications.