Meta is a tiny and header-only C++11 metaprogramming library released under the Boost Software License. Supported compilers are clang >= 3.4 and gcc >= 4.9. To compile with meta you just have to:

#include <meta/meta.hpp>

You can find documentation online here.

For a quick start see Eric Niebler's blog post: A tiny metaprogramming library. (Note: the names in Meta are different from those describe in the blog post, but the overall design remains the same.)

To generate the up-to-date tutorial and documentation run make doc in the build directory (requires Doxygen, LaTeX, dvips, ghostscript).