Write a program in language A which outputs a program in language B where:
- Language A != Language B
- The output is itself a solution to this question.
This is a popularity contest. If you want to define your own BNFs/grammars for this, feel free, but try not to make it too boring by doing so.
EDIT: The more languages it ends up generating code in, the better (in my opinion).
EDIT2: Try to use languages that are not similar (I.e. generate the code in a different family of languages). (E.g. C to Scheme)