ParPy is a Python library for GPU acceleration of Python code. Using ParPy, you annotate statements in a Python function, providing a high degree of control over how the code parallelizes on the GPU at the call site.
See the installation instructions on the ParPy website.
The ParPy documentation contains tutorials walking through concrete examples of parallelization. In addition, the test directory contains many programs using different aspects of parallelization available on ParPy.