I like to pimp code generation, DSL's, and little languages as solutions to software engineering problems. A large number of people consider this "deep magic" and thus, not to be used as casually as, say, good Object Oriented design techniques, or relational modelling techniques. Well, I disagree, and since I saw this in the wild usage of code generation, I thought I would point it out.
Via
Sam Ruby someone has
implemented an HTML5 parser in "Java" and then using some various compilers, including a custom one to cross compile to C++ for Gecko, to translate it into target platforms.
There are lots of other uses of this technique, but that's one I saw today.