libjmmcg is a basic, low-level library with pretensions to implementing features above and beyond (but not necessarily better than!) those implemented within the Standard C++ Library and the Boost Library. It features a library for multi-core or multi-chip SMP parallelism, a suite of hashing algorithms, functions for raising numbers to integer powers, a generic factory wrapper and a generic, multi-threaded, read-only cache (which uses PPD), arguably the world's worst sorting technique, trace output, exceptions that have the file, line, revision, function, and argument details, string utilities, logging, simple command line processing, and much more.
ChaiScript is an embedded scripting language designed from the ground up to directly target C++ and take advantage of modern C++ development techniques. Being a native C++ application, it has some advantages over existing embedded scripting languages. It uses a header-only approach, which makes it easy to integrate with existing projects. It maintains type safety between your C++ application and user scripts. It supports a variety of C++ techniques including callbacks, overloaded functions, class methods, and STL containers.
LIME is a dynamic programming language with a LISP-like syntax. It features partial function application, eager and lazy evaluation, call-by-value and call-by-reference, macros, reading/writing LIME code as data, a standard library including infinite streams, and an interactive mode with auto-indentation.
Metacza is a language and its compiler which produces output in the C++ Meta Template Language. Its concise syntax makes Meta Template Programming much easier. Metacza allows you to write programs using boost::mpl, and to produce C++ header files that can be used on their own. Programming without boost::mpl is also supported. Metacza is a higher order language with closures, let, and lambda.