This is really great stuff. Although I haven't done any serious Arc hacking yet, it's already had a big impact on how I code in Ruby. news.arc will be a great source of ideas.
BTW, does anyone have any deployments planned? Does it make sense to deploy production sites using news.arc, or is keeping up with Arc's evolution at this stage too much of a challenge?
I imagine it would be OK if you don't need to keep up with changes.
It's more a question of the stability of the language specification. I don't doubt the code is solid enough for production sites; it's just that keeping up with Arc's evolution might be difficult. But as I pointed out, you might not need to do that. (I edited the original comment to be more clear.)