3-on-3 Defensive DrillBy Dr. James Gels, from the Coach’s Clipboard Basketball Playbook
Setup: Divide your squad into 3-man teams (you may have one or two 4-man teams where the players rotate in and out, if the numbers don't come out exactly even). These teams will take turns competing against each other as outlined below. Only two teams will be on the floor at a given time, offense and defense. Split the teams up fairly (no "stacked" teams), and have at least one guard and one post player on each team.
The Drill: Play half-court, man-to-man defense at all times. Coaches referee. Points are scored only by the defense. The defense gets one point whenever they stop the offense and get possession either by a defensive rebound, a steal, a forced turn-over, forced bad pass, etc. The idea is for the defensive team to stay on the floor as long as they can, because it's the only way you can accumulate points.
No points are awarded for baskets made. However, if the offense scores, then the defensive team must leave the floor and the offense now becomes the defense (enabling them a chance to accumulate points), and a new team comes out on offense. Also, if the offense commits a turnover, or fails to score, they must leave the court and a new team comes out on offense. So there is always a penalty for failure... the team who fails (whether offense or defense) must leave the floor.
If the defense commits a foul, this also results in them being kicked off the court and the offense now becomes the defense and a new team comes out on offense.
Pick a set number of points... the first team to obtain that point total are the winners.
This drill will help pick up your intensity, and the players usually enjoy this "game".