Rack, recently announced at version 0.2 by Christian Neukirchen, is a minimal, modular and adaptable interface for developing Ruby web applications. By wrapping HTTP requests and responses in the simplest way possible, it unifies and distills the API for web servers, web frameworks, and software in between (the so-called middleware) into a single method call.
Classifier is a Ruby gem developed by Lucas Carlson and David Fayram II to allow Bayesian and other types of classifications, including Latent Semantic Indexing.
Handshake, currently in version 0.3.0, is an informal design-by-contract system written by Brian Guthrie in pure Ruby. It's intended to allow Ruby developers to apply simple, clear constraints to their methods and classes.
Andrzej Krzywda has put together a solid, 15 point tutorial on how to build a Rails application from the ground up using Test Driven Development (TDD) techniques. This is pure gold because so few of the books and "how to build a blog in 5 minutes" type articles bother to cover testing and Andrzej shows how to get into the habit from almost the first step.
Joyent Slingshot allows developers to deploy Rails applications that work the same online and offline (with synchronization) and with drag into and out of the application just like a standard desktop application. Check its two-minutes tutorial to get a feel of how you can make it work.
Data Structures and Algorithms with Object-Oriented Design Patterns in Ruby is an online book (free to read!) by Dr. Bruno R. Preiss, an incredibly well qualified engineer and computer scientist. It covers all of the various data structures and algorithms that beginning Computer Science students have to learn, but from a Ruby perspective and using object oriented design patterns.
The book itself is now a few years old, but I've only just come across it and it still seems relevant although, rather sadly, the on-page code is in graphics only (a ZIP file containing the source is available) and feels like a line-by-line conversion from C++ rather than true Ruby code. Still, if computer science, data structures, and algorithms elude you to any degree, and you want to learn about them while following Ruby code, it's a good place to start. There are also versions for C++, Java, C# and Python available from Bruno's homepage.
(photo credit: RBerteig)
Slideshare is like the YouTube or Scribd of presentations and slideshows and it features a few good Ruby and Rails related slideshows that are worth flicking through. This post links to some of the best:
(credit: Chance Gardener)
