Setup. Two goals 25 metres apart. Two teams, one behind each goal line. Give every player on a team a number, so each number has an opposite on the other team. Coach on the side with the balls.
How it runs. The coach calls a number and throws a ball into the middle. Those two players sprint out and play 1v1, trying to score in the other team's goal. One team-mate from each side goes in goal. Play stops when the ball is dead or after ten seconds. A goal is a point. First team to five.
Make it harder. Call two numbers for a 2v2. Then the ball is thrown high, so the first job is to win it in the air.
With 4 keepers. Two teams of two: one plays out and one keeps goal each time.