Makes me think of Xanadu.

It's finally happened: Arc's out [via gavin].

Why release it now? Because, as I suddenly realized a couple months ago, it's good enough. Even in this unfinished state, I'd rather use Arc than Scheme or Common Lisp for writing most programs. And I am a fairly representative Lisp hacker, with years of experience using both. So while Arc is not the perfect Lisp, it seems to be better for at least some kinds of programming than either of the leading alternatives.

From arclanguage.org:

the extent we can influence whatever customs are associated with Arc, we'd like to propose three principles.

Number one, expect change. Arc is still fluid and future releases are guaranteed to break all your code. In fact, it was mainly to aid the evolution of the language that we even released it.

Second, we'd like to encourage a sense of community among Arc users. If you have a question or a suggestion, share it with everyone in the forum. And if you know the answer to a question you see in the forum, help out whoever posted it by replying. Be nice; if someone's being a dick, don't let the anonymity of forums tempt you to reply in kind.

And finally: It's not a coincidence that we wrote a language for exploratory programming rather than the sort where an army of programmers builds a big, bureaucratic piece of software for a big, bureaucratic organization. Exploratory programming is the fun end of programming, and we hope that will be the guiding principle of the Arc community.