2D Z-Sort

var shapes:Array = new Array();

for (var i:int = 0; i<300; i++){
	var s:Shape = new Shape();
	s.x = Math.random()* stage.stageWidth;
	s.y = Math.random()* stage.stageHeight;
	s.graphics.lineStyle(0,0x000000);
	s.graphics.beginFill(0xCCCCCC);
	s.graphics.drawCircle(0,0, Math.random()*s.y / 5);
	shapes.push(s);
}

// comment this out to remove sorting
shapes.sortOn("width", Array.NUMERIC);

for (i = 0; i<shapes.length; i++){
	addChild(shapes[i]);
}

This uses Array.sortOn() to do some basic z-sorting based on the width property of some circle shapes.