Nearly 35 years ago (on April 20, 1984 to be precise), the Montreal Canadiens and Quebec Nordiques faced off in a playoff game that descended into a bench-clearing brawl at the end of the second period, as bad blood between the two provincial rivals boiled over. Both teams were eventually separated and sent to their respective locker rooms. When it came time to go back out for the third period, the referees had not yet sorted out the penalties, so both teams came out and the brawl commenced again.
It is one of the most famous incidents between the two franchises, and resulted in 198 minutes of penalties and 10 game misconducts.