http://www.10gen.com/blog/2008/12/ruby-support-on-10gen

It's official: the 10gen open source cloud computing platform
(http://www.10gen.com) now supports Ruby and Rails. See the blog post
for details and links to documentation, the SDK, mailing lists, and
more.

The 10gen platform includes a multilingual app server and distributed
document database. You can grab the source or download a pre-built
SDKs from the Web site.

Note: the Rails support does not yet include ActiveRecord. We're
working on it. In the mean time, you can access the database via an
AR-like set of classes or "raw".

Jim
-- 
Jim Menard, jimm / io.com, jim.menard / gmail.com
http://www.io.com/~jimm/