Pypy has a (currently, software) transactional memory branch that is trying to remove the python GIL without changing the semantics http://pypy.org/tmdonate.ht

Pypy has a (currently, software) transactional memory branch that is trying to remove the python GIL without changing the semantics http://pypy.org/tmdonate.html http://pypy.org/tmdonate.html (has the best executive summary of what the branch intends to accomplish)