I've tried really hard with eslisp to defy Greenspun's Tenth, and to do justice to the Lisp tradition. The macros in eslisp are actual macros with scope and proper hygiene. They can perform arbitrary computation, and can arbitrarily modify the AST. You can even access the macro table during compilation to completely gut the language from the inside if you want.

So I guess the goal is to be a purpose-designed, fairly well specified, only somewhat buggy, slower-but-not-debilitatingly-so implementation of 80% of Common Lisp. :)