(INTERMEDIATE BLENDER TUTORIAL)

Go to the text editor. Make a new file. Copy and Paste this code into the file:

from Rasterizer import showMouse
showMouse(1)

Save the text file.
Now give it a name in the pull-down menu (showMouse).
Then, in the logic panel of any empty object (or camera) add only a sensor and a controller.
Set the controller to Python, then put the name of the text file (showMouse) in the field.