One of my favorite [tag]motion offense basketball[/tag] drills is lay-ups without a [tag]basketball[/tag].  I have used this quite successfully with middle school basketball teams.

Form 2 lines on opposite sides of the basket and simulate shooting both right and left handed lay-ups emphasizing the proper form.

Do this for about 5 mins. Then move to the foul line and begin to introduce the ball in the form of a pass.
The players continue to move towards the basket looking for a pass.
They may get a pass immediately and shoot a jumper or receive a pass for a straight lay-up or reverse lay-up. They may continue through the lane and receive a pass for a turn a round jumper or continue out toward the wing and receive a pass for a 3-point shot.

What is being learned in this [tag]basketball drill[/tag] is moving without the ball, learning to move toward the basket expecting a pass at anytime and learning how to move off of screens and pick for the open shot.