VisionPyg is a minimalist approach to psychophysics using Python. The purpose of the package is to allow one to quickly write simple experiments that use visual stimuli. VisionPyg differs from other similar tools in the amount of code and minimal dependencies. VisionPyg's “main” library is a single file with around 400 lines of code.

You can download VisionPyg from here.

VisionPyg requires only Python to run. The few other essential dependecies are bundled with the package. However, we also suggest installing Numerical Python (numpy). VisionPyg is meant for scientists and therefore it is very likely that even the most simple experiment will require some math. 

New to Python? 
If you are completely new to Python, and do not want to hit any obstacles while installing Python and its scientific packages, I suggest installing the free version of Enthought Python Distribution, recently rebranded as Canopy Express. For Mac OS users I found this distribution is the only way of getting all scientific packages (especially Matplotlib) working without a problem.

A simple MATLAB experiment VisionPyg allows stimulus design and control from MATLAB. The experiment will be running in Python, MATLAB will be used to remotelly control this experiment. The Python program that will “listen” to the MATLAB commands is a simple experiment with no stimuli and remote control component included ....