This aplication can use any webcam to track colors, an then emulate the movement into an input device. This means, you can “lock” on to anything that has an apropriate color, fx a bright yellow, green red or other strong collored, book, pen, print out, anything. It can even lock on to th ecolor of your LIPS ;D
– and now you have a gesture controlled input device 😀
I have printed out a “wheel” with a green colored bar on it, and use it to play trackmania nations. The software is free, the game is free, and i guess you can find something that has an apropriate color, for free.
So go try it! . but obviously you need a webcam 🙂
You can get print outs for wheels, and “controller” programs for lots of games on the website: