I'm glad someone else is coming with a solution other than maven. Maven is one complicated beast.

I don't get it. The FAQ implies they aren't using jar files, so are they providing a custom classloader instead? If they inherited multiple-version support from rubygems, how do they know which version I want visible?

See also buildr, which attempts to be a drop-in Maven replacement using a ruby DSL built on top of rake. http://buildr.apache.org/

And this is why having the main Ruby gem repository completely open source rocks :)

why is it in Ruby?

As opposed to, say, Clojure or Scala ?

Why write it in Clojure, as opposed to, say, Scala or JRuby?

Because the finished, mature, best in class ruby implementation is completely open source and is just sitting there for anyone to adopt, right now?

No need to re-invent the wheel. : )