Denys Bondar and I, just released to the public: PyNewtonCUDA
This program is able to propagate a large number of classical particles using GPU technology. The code is written in Python and PyCUDA, which allows to write high-level code for GPU programming while maintaining very high performance.
You can download the code with the following command
svn checkout https://py-newton-cuda.google.com/svn/trunk PyNewtonCUDA