PsychoPy is an open-source application allowing you run 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™ ).
PsychoPy is unique in giving you a choice of interface: use the Builder interface to build rich, flexible experiments easily or use the Coder interface to write extremely powerful experiments in the widely-used Python programming language. The best of both worlds!
Latest version: 1.85.0 was released Feb 2017 with initial proof-of-concept of online experiments. Beware - these are bound to be buggy so only use if you know what you’re doing. And READ THE DOCS. See the full Changelog