2 on 2, Coach at the foul line, 2 offensive, two defensive.
Coach has the ball at foul line. 2 players are at post as offensive players, 2 other players are playing defense. Coach shoots ball, purosely missing. Players must box out and go for ball. Which ever team rebounds then becomes the offensive team and must score, the non rebounding team must play defense. Drill is done once someone scores, or a certain amount of time passes. The 2 players that started out in the defensive position move off court, the 2 players that started off in the offensive positions move to defense and two new player move on at the offensive positions and drill resumes.
Make sure players are boxing out, rebounding high, going for ball. The 2 on 2 part (or one on one part) is secondary.
For younger players, remove the 2 player, and have just two players at the post. They must scramble for the rebound and once they get it, play one on one until someone scores or certain amount of time passes.
Boxing out, rebounding.
This basketball drill is licensed under a Creative Commons License. This drill is from Pål Degerstrøm at www.degerstrom.com/basketball.