Moscow ML Home Page - surprisingly, I hadn't come across this before. It's a small SML bytecode compiler that now implements the full language scope and standard library. Much slimmer than the large SML/NJ and also requires fewer resources than SML/NJ or MLton. Very useful for small tools (and installable on the Mac with MacPorts - just like SML/NJ and Poly/ML, the other two major ML compilers).