In short: a game in which the groups get different shooting assignments.
Organisation: two, three or four teams per basket. The players take turns to shoot. After each task the groups leave the ball behind and move on to the next basket.
The baskets are spread around the room. The groups are divided over the baskets, where uneven size of the groups is not a real problem. The trainer gives an assignment (see below for some examples). The group that completes the task first gets a point. After that the groups all move one basket, especially when the circumstances per basket are different (sun, floodlights, puddles, strong wind, scoop baskets etc.). It also keeps the momentum of the game which is especially the case when the trainer allows the groups to start immediately, even if not everyone is ready yet. The winner is the group that has gathered the most points after, say, 15 minutes of play.
These exercises do not fit into a competition format, as there is a tendency to indicate something less difficult. When the goal is to learn or improve a certain technique, don't offer all the possibilities mentioned above in one training. Experience shows that the players will then 'show off' too quickly.
Suitable assignments are (at lower levels, smaller numbers of goals to be scored):
Also "crazy" assignments work very well in this game: