From rule 56a:
A player who is deemed to be the instigator of an altercation in the final five (5) minutes of regulation time or at any time in overtime, shall be assessed an instigator minor penalty, a major for fighting, a ten minute misconduct and an automatic one-game suspension. The length of suspension will double for each subsequent offense. In addition, the player's coach shall be fined $10,000 -- a fine that will double for each subsequent incident.
note: No team appeals will be permitted either verbally or in writing regarding the assessment of this automatic suspension.
So what happens as a result? Incidents like last night, where just inside the 5:00 mark of the third period, a player from the Atlanta Thrashers decides to take a cheap shot on Capitals' superstar Alex Ovechkin, with exactly 4:16 left in the game. This isn't the first time this has happened this season either. In their second game of the season, the Canes' Tim Gleason went knee to knee on the same player about twenty feet away from the first incident.
By eliminating the potential for retribution, the league has given players carte blanche for dirty play at the end of the games. The fact that neither player was suspended furthers the issue.