The "dirtiest game is Russian ice hockey history" - which is saying a hell of a lot, if you ask me - started after AK Bars Kazan scored a late goal to the displeasure of the opposing Chelyabinsk. A delicious mass brawl ensued.
One can assume the fight was a result of game-long antagonizing on both ends, but I'm pretty sure it was just frustration out of not being able to spell anyone's name.