Divide your team in half and line up to play a game. Players assume as many offensive/defensive positions on the field as they can. The focus of the exercise is to teach children to play the position and not to form a massive "scrum" that simply follows the ball. To do this the coach must actively watch as play develops. If two players of the same team get within arms reach of each other play is stopped (whistled dead) and one of the two players is sidelined for one minute (My watch has a countdown feature that I use for this purpose). This affords the opposing team a brief power play and teaches the "offending" player to play the open field and not fight with other team members for the ball. There is no goalie and the teams must shoot at one cone to score which is positioned where the normal goal would be located. The game is for a pre-determined time (say 10 minutes) and the team with the most goals wins. (obviously) Lots of fun!