This is a great way to work on special teams. The nice thing about this drill is that it requires a lot of players. Many times when practicing special teams, there are lots of players watching from the bench. Split up your team into two teams. Each team has a power play unit and penalty kill unit on the ice at the same time. In this diagram the green power play unit is in one end going against the blue penalty kill unit. In the other end you have the blue power play unti against the green penalty kill unit. One puck is in play at a time and it can start with the power play unit on either side. So lets say the green team starts with the puck. The green power play goes against the blue penaly kill until the blue penalty killers get the puck and send it the length of the ice to the blue power play unit. The blue power play unit then plays against the green penalty kill unit until the green penalty killers can ice it back down to their power play.
This drill can also be a great way to scrimmage another team in special teams or if you have to share the ice with another team.