I was reading an age old story from Gibson Research Corporation about their 2001 Denial of Service attacks. Its a really good read for anyone interested in network security and networking in general, but the part I found of interest was his link to the official RFC 1459 document, outlining the standards for the Internet Relay Chat (IRC) protocol.
I wont bore you all with the details, but since I recently wrote my own IRC interface for a PHP script, this was of significant interest to me.
Check it out here.
GRC.com also hosts some other interesting articles. His story about the DoS capabilities of Windows XP is a great read (found here), as well as his story about their second DDoS. Also of note are some of the programs he has developed, all of which can be found directly from GRC.com.