It is initiated by a 2-3 person conversation whereby each person adds every online contact they have, creating one mega-convo. This is followed by fast, erratic postings of words in capitals such as 'PENIS' and 'DILDO' and 'MMM COCK' and 'FUCK SHIT CUNT' etc... and often includes adding pornographic images and moving emoticons to spam and disgust the added people.
It is called the msn madness minute, because almost every time either all the people will leave (the online people anyway) or msn will crash and burn due to the insane ammount of people added to one convo.
The glory that is the msn madness minute is reinforced by the fact that it is not able to determine who started it, as well as which people added who, but one can summise that the person yelling 'DICKS AND TITTIES' probably had something to do with it (although some people who have been added give there two-cents worth!).
One last idea for the madness minute is of course to pretend you are someone else by changing your display name. In a conversation that might be 40 people strong, saying 'look guys, ive added you all to give you some really important information --- im gay'. The stupid fucks that believe you will no doubt spread this and hopefully the real person has to deal with it (LOL).
John: fuck oath man... oi lets msn madness minute this shit... just go all out with the vulgarity
Craig: kk... add those mother fuckers
and the msn madness minute begins