I have recently come across a very cool java applet developed by Anatoly Zenkov (kickass idea for the flash background on the site, by the way). It’s a quite simple, open-source code that tracks your mouse movements on the screen and creates a visual representation of your activity.
The following image was generated while I played through the Retrieve the IFF device mission in Mass Effect 2. I superimposed the graphic against some watercolor splashes, since with all the doodles QubaHQ started becoming a bit too monochrome.
The applet is free to download for both PC and Mac. You can also see more images generated by this app on Anatoly’s Flickr account.