I talk about Lathe at http://arclanguage.org/item?id=11610, which links to a blog post, which links to the GitHub repo thaddeus already linked to. ^_^
The blog post is still a pretty comprehensive look at Lathe. A bit has happened since then, but the most useful thing is Jarc compatibility, and even that isn't on the master branch yet; Lathe's approach to namespaces still doesn't harmonize with Jarc as well as I'd like.