I'm about 22 years late on this but I really didn't know about this event until earlier today. It's a brawl between Canada and Russia during the 1987 World Junior Hockey Championships.
I've never seen anything like it, especially when you consider the setting. It was the final game of the tournament. Canada led 4-2 on its way to a possible gold medal. Future NHL stars such as Theo Fleury, Brendon Shanahan, Pierre Turgeon, Sergei Fedorov, Alexander Mogilny and Vladimir Konstantinov played in the game.
But with 13:53 remaining in the second period, the worst bench-clearing brawl I've ever seen broke out. Fleury was at the epicenter, which should come as no surprise. Turgeon and Canada's backup goalie were the only two to not join in the fight. Turgeon remained on the bench with his head down while the 20-minute melee went on. His inaction was deemed unforgiveable by some teammates.
Both teams were kicked out of the tournament, meaning Canada went home without a medal. The 2010 WJC is under way now in Canada. But I doubt anything like this will break out.