A new version of this scenario was uploaded on Wed Dec 21 10:27:29 UTC 2011
Now you can control greenfoot actors with your fingers! All you need is a camera and the (free) reactivision software; print a few fiducials (markers) and move them in front of the camera: the starfish actors in this scenario will follow them.
Cheers,
Andrea
PS Sorry, but it will not work as applet, you need to open this scenario in greenfoot on your machine, and follow the instructions to download the required (free) TUIO software :)