I'd love to have one of these for Ruby. Every time I want to try out something written in Ruby I run head-first in to the packaging problem - Debian and Ubuntu don't appear to like shipping a working gem (presumably because it conflicts with how apt likes to do things) and the documentation on how to resolve the resulting inscrutable error messages isn't particularly easy to find. The Mac is a bit better, but I still run in to problems far too often.

I'm pretty sure a "Ruby Ecosystem, An Introduction" guide is exactly what I need.