Laurence Tratt: Fast Enough VMs in Fast Enough Time. Interesting article by the developer of Converge (a language that picks up and combines ideas from Lisp - macros - and Python - indentation for scope and parts of the syntax) about RPython, the base language behind PyPy. This way you also understand a bit more what role RPython plays exactly (namely the implementation language for interpreters that automatically get a JIT).