If you are interested in Rebol, have a look at http://www.red-lang.org/ http://www.red-lang.org/ which is more modern (and not just interpreted but also compila

If you are interested in Rebol, have a look at http://www.red-lang.org/ http://www.red-lang.org/ which is more modern (and not just interpreted but also compilable) language very close to Rebol. And it's OSS of course. It's still alpha version in development, but with good backing and very dedicated team.