4 - Caps' current "Bowman Index" score (their combined ranking in power play and penalty kill efficiency), which is tops in the League. You know about the team's red-hot power play, but the penalty kill has been hot of late, as well; per Caps Today, the Caps have killed 13 consecutive penalties and 14 of their last 15 over their last five games. That brings their season percentage up to 87.1%, good enough for 3rd-best in the League to go with their top-ranked power play.
By the way, Toronto comes in second with a Bowman Index of 7 and Colorado is close behind with 9. Worst in the League? Well, that would be our old friend Bruce Boudreau and the Anaheim Ducks... who come in with a score of 54. Yikes.