In a fit of why-the-hell-not, I've just started writing my first gem for Ruby, which is going to be a wrapper around the AMEE carbon calculation engine. It's still in a very early incarnation, but more will be forthcoming soon. At the moment it can authenticate, and parse DataCategory nodes. DataItems and DataItemValues will be following after a short (UK-based) holiday. Source code and installation instructions are available from GitHub.