PaiMei, is a reverse engineering framework consisting of multiple extensible components. The framework can essentially be thought of as a reverse engineer’s swiss army knife and has already been proven effective for a wide range of both static and dynamic tasks such as fuzzer assistance, code coverage tracking, data flow tracking and more.
The largest sub-component of the framework, PyDbg, will likely be of most interest and use to a wide audience. PyDbg is a pure-python win32 debugger interface. See the PyDbg documentation for a good idea of the exposed feature-set. PyDbg may be extended in the future to provide a cross-platform debugging API across both Windows and Linux. 64-bit Windows support is also being considered for addition.