This can be done with as few as 8 players and as many as 12 players per group.  Start with a 15 yard square (this size can be altered depending upon the age/needs of the players).  There should be 2-3 players in each corner of the square.  See diagram below for set up

Player 1 starts with the ball and passes the ball to Player 2.  Player 1 then runs toward Player 2 who one touches the ball back to Player 1.  Player 1 then passes the ball to Player 2 who is running down the line toward Player 3.  See diagram below

This activity works on double passes, and wall passes.  As soon as Player 2 receives the second pass from Player 1 he/she starts this sequence over again by passing to Player 3 and they do the exact same thing.

Once the pattern is understood by all, a second ball gets added so that at the same time Player 1 is passing the ball to Player 2, Player 3 is passing the ball to Player 4. Only add the second ball once the players are proficient with one ball. See diagram below

This activity will get everyone moving and having to time and pace their passes and runs properly and is a great way to work on passing, movement and combinations.