Looking for a paragon or two

I saw a posting here recently about “The well tempered Ruby application”
(http://rubyforge.org/projects/hello/), an example/template project that
demonstrates standards and best practices for structuring your Ruby
project. Things like a rakefile, rdoc comments, layout of
subdirectories, etc. I think this is a beautiful idea, and one that I
would love to study once it’s closer to being done.

In the meantime, can anyone recommend one or more RubyForge projects
that are well-thought-of in the Ruby community, in terms of structure,
professionalism, and so on?