QuakeNet
QuakeNet is currently the largest Internet Relay Chat (IRC) network, with a peak average of about 100,000 users and 60,000 channels. The network was founded in 1997 by Garfield (Henrik Rasmussen, Denmark) and Oli (Ola Ingvarsson, Sweden) as a new home for their respective countries' Quake channels. At its peak on February 8, 2005, the network recorded 243,394 simultaneous connections.
Read more about Quakenet.