For a while, I've had this program called Colorpic, which allows you to take colors from anywhere on the screen. Recently I've started using it again.
It has a preview pane that shows what the mouse is over and magnifies it. You can also have it draw a small box in the preview pane, showing where the cursor is, and a grid, one dot for x pixels.
After messing around, I found some pretty crazy recursion stuff, and it ended up making fractals

When yuo move the cursor around it goes mad, and it looks like you're flying into it or something.
Has anybody else found something like this?
Edit: found link to program
http://www.iconico.com/colorpic