Start with 2 players in the paint at each end of the court and a single file line at half-court.
A player at one end of the court bounces the ball off the backboard and rebounds. He immediately outlets to the first player in line at half-court (who has stepped inbounds) and called for the ball. The player at half-court centers the ball and the two players from the starting end fill the lanes to attack the two players waiting at the opposite basket in a 3 on 2 situation. (NB: two players immediately replace them at the original end in preparation for the continuation of the drill).
Play continues until the defense gets a steal, rebound, or charge - or the offense scores. The defenders immediately outlet the ball to the next player in line at half-court and attack the other end. Two of the original offensive players remain to defend the next trip back and one joins the end of the line at half-court.
Minimum of eight
This is a very fast drill and players can tend to get 'out of control' as they tire after several minutes of play.
Besides basic fundamentals, I stress:
Defensively: Defend in tandem with the top man stopping the ball just above the top of the key and forcing a pass or bad shot. Once the pass is made, the back man takes the ball and the top defender must fall back through the middle to stop the cross-court pass. Encouragement is given if the defenders can force the offense to shoot from outside of the paint.
Offensively: Center man to try to drive all the way but, if stopped, to use a give and go with the opposite wing man replacing him at the top of the key looking for a pass for an easy shot if the ball cannot be dumped inside. Try to avoid having the offense make more than two passes.
Attacking and defending 3 on 2
This basketball drill is licensed under a Creative Commons License. This drill is from Pål Degerstrøm at www.degerstrom.com/basketball.