For the record, if you do that system, and you put it backwards, as in, having the wiimote in front of the screen pointing at you, there is no reason you can't do the 4 point configuration on thin air, since its the dot it watches, not wither it touches the screen or not. (he is doing something similar in another one of his videos, but there is no reason you can't use your light pen from the previous project as opposed to trying to make your fingers reflect)
Which gives you the awesomeness of being able to control your computer from far away just by moving your hand around, miniority report style.
Its not really useful for anything, I think the best program to play around is Google Earth because its really intuitive giving it momentum etc, conductor style.
You can paint as well but you will probably end up being a "abstract impressionist", but hey, you are painting on the air, and colours appear on the wall/screen dude!
That's like, deep performance art contemplating the merging of the human and machine condition or something.
Now to rig that with some kind of coordinated based music generator...
*Slam's hand on Mleo's back* Well if it isn't my Good Friend Mleo, the programming supergenius. *nod nod, wink wink*