Minigrace, currently maintained by Andrew Black (based on Michael Homer’s thesis work) is written in Grace and capable of compiling to native code via C and to JavaScript. The compiler should work on any POSIX-compatible system with GCC. For more details, see the documentation inside the source tree.
There are tarballs that require only a C compiler to build. You can also git clone git://github.com/gracelang/minigrace.git, which knows how to build itself using the tools/tarball-bootstrap -a script to bootstrap from a recent version.
There is a prototype client-side web front end. This is adequate for many student programs, and supports simple graphics. We recommend running it in Firefox or Chrome.
There is a Minigrace mailing list for discussing issues related to the minigrace implementation.