After creating fire, bubbles, fairy dust and whatnot with the bitmapdata in flash 8, I wanted to try and make a clip react to motion :beam:
www.avalon-rev.dk/engine/newEngine.html
Writes and copies bitmapdata per frame, then creates a black/green image from the differenced images, creates motionpoints per 5th triggered point. The ball reacts according to each motionpoints position 
fla: www.avalon-rev.dk/engine/newEngine.fla
video: www.avalon-rev.dk/flash/engine/newEngine.rar
*requires webcamera and plash player 8