I want to present some rough ideas where PyPy's flexible architecture makes good usecase examples and some overview of that architecture. Details: 1. Stackless features, composable deterministic concurrency, picklable coroutines, an overview how this is implemented 2. Transparent proxy, remote objects. Need to make examples work under pypy-c (especially py.execnet) 3. Digging deeper - compiler toolchain overview, what is RPython, why C considered harmfull. 4. Multiple backend choice, (in)flexibility of RPython, duality, CLI, JVM etc. !!! 5. Extension compiler 6. JavaScript backend, unittest under python run on browser (not-completed). 7. (in)famous offline partial evaluation, JIT, some demos. 8. Prolog interp as an example of using compiler toolchain? Method: Some RPython written - presentation viewer???