Not really a game at all, but the web-master thinks it is interesting and fun (there again, the webmaster thinks that designing web-sites is interesting and fun...).
You play the game in a new window which will open miraculously when you click 'Start Colour Mixer' below.
Just use your mouse pointer to slide the colour sliders to increase the red, green and blue values of the background of the page.
If you want to make a game of it, mix and match to see if you can get the coloured words to disappear.
Start Colour Mixer