PsychoPy is an open-source package for creating psychology stimuli
in Python (A real and free alternative to Matlab). PsychoPy combines
the graphical strengths of OpenGL with the easy Python syntax to give
psychophysics a free and simple stimulus presentation and control
package.

The goal is to provide, for the busy scientist (including me!), tools
to control timing and windowing and a simple set of pre-packaged
stimuli and methods. The code is platform independent, using Python
and C libraries that are widely available.

WWW: http://www.psychopy.org/