You should have four baskets (2 crosscourts) and the players should be divided into four teams of either 3 or 4 players. You will need only three balls.
The topic is now to play a 'regular' game of basketball. All of the four teams will be playing against each other at the same time, i.e. every team will defend their own basket and will play offense on one of the other three baskets (they decide for themselves and can decide to play offense on another (maybe unguarded) basket in the middle of an offense).
The subject is to communicate so that the players are aware of who controls the balls, who's on defense, who's on offense, is there a basket with no defense and so on.
When a basket is made the team on defense is the only team who can bring the ball back into play. If they are allready in offense they don't have to bring in the ball. This way it is actually possible for one team to control all the other balls. This is however not neccesarily a good thing, because then they will have three teams playing defense on them and going for the steal.
I made up the game when the mainbasket in the gym was broken and the players(juniorboys) really had a lot of fun. The intensity was high and the fun never took the concentration off of the mainpoint of the game: to be better at their offensive and communicative skills, to see the court, their teammates and to read the game as it unfolded. I think it is a good drill to use once in a while when practices are getting too boring or predictable.
Have fun and work out your own rules and regulations. Try to work with the skeleton and you will probably make up a drill thats even better.
12 or 16
Be there and have fun! The players will have a lot of problems in the beginning because of the different (and therefore difficult) rules. But if you are there taking an active part of the drill, they will keep up the good work.
Stop the drill once in a while and talk to them about the rules or 'coachingpoints' and adjust to the discussion. I.e. either change the rules (if that's the problem) or talk to the players and tell them what they should be looking for.
This drill has been changed a lot of times, and now I have a great drill that my boys really like to 'run', but when I use this drill with others team it's not the same. I think it is all in the process.
The drill works for me and my players because they, during the 'invention', learned a lot by their mistakes and the adjustments we made. So give it a shot and maybe it will work for your team.
Focus/concentration, communication, read'n'react
This basketball drill is licensed under a Creative Commons License. This drill is from Pål Degerstrøm at www.degerstrom.com/basketball.