PsychoPy is an open-source application to allow the presentation of stimuli and collection of data for a wide range of neuroscience, psychology and psychophysics experiments. It’s a free, powerful alternative to Presentation™ or e-Prime™, written in Python (a free alternative to Matlab™ ).
Latest version: 1.80.05 was released June 2014, with many improvements to the user interface (e.g. dialog boxes), more precise degrees of visual angle (optionally correct for flat panels) and many bug fixes
See complete Changelog for complete list of additions and fixes