So this is a VERY rough attempt at tracking objects based on color. Again, you need a webcam.
1) Fill the middle circle with a nice bright high contrast color
2) Click the COLOR button
3) Little crosshairs track the color (er, somewhat)Color Tracking
A brightly lit room helps. This actually worked worse and worse the later/darker it became.
With my best efforts I don't think this could be viable for a released product but it was an ejoyable experiment. What I was really hoping to do was track the color and then add some gesture recognition. Then I could cast spells a la Harry Potter or something silly.
A number of people have contact me about the code for this. I must warn you, IT WORKS POORLY EVEN UNDER THE BEST CONDITIONS! But you asked so here is the source.