Cramp is a fully asynchronous real-time web application framework in Ruby. It is built on top of EventMachine and primarily designed for working with larger number of open connections and providing full-duplex bi-directional communication.

Padrino is a ruby framework built upon the Sinatra web library. Padrino was created to make it fun and easy to code more advanced web applications while still adhering to the spirit that makes Sinatra great!

Logic-less templates.

Available in Ruby, JavaScript, Python, Erlang, PHP, Perl, Objective-C, Java, .NET, Android, C++, Go, Lua, ooc, ActionScript, ColdFusion, Scala, Clojure, Fantom, CoffeeScript, D, and for node.js.

Generate HTML slides, with syntax highlighting, with Markdown.

A toolkit for building presentations in HTML. Consists of a generator and a basic set of JavaScripts and CSS. That alone will give you a working system for creating and showing slides from inside a web browser. You can use a theme, customize it, or even modify Shining so it does what you'd like. Features brain-dead easy deployments to Heroku, so you can host your presentations as an application for free, provided you have an account.

A Ruby gem that lets you create slide shows and author slides in plain text using a wiki-style markup language that’s easy-to-write and easy-to-read. The Slide Show (S9) project also collects and welcomes themes and ships “out-of-the-gem” with built-in support for “loss-free” gradient vector graphics themes.

Rubinius is an implementation of the Ruby programming language providing performance, accessibility, and improved programmer productivity.
The Rubinius bytecode virtual machine is written in C++, incorporating LLVM to compile bytecode to machine code at runtime.

a side-by-side reference sheet. really, really useful.

rbenv lets you easily switch between multiple versions of Ruby. It's simple, unobtrusive, and follows the UNIX tradition of single-purpose tools that do one thing well.