RubySlide

Padrino is a ruby framework built upon the Sinatra web library.

pure Ruby DB toolkit

Using Server-Sent Events, WebSockets etc. for real-time web communication.

Splitting an app up in different processes is great for performance and scalability. The downside, however, is that it becomes much more complicated to get the app and all of its parts running. Foreman is an attempt to make this easier. Using foreman you can declare the various processes that are needed to run your application using a Procfile.

Chef is an open source systems integration framework built to bring the benefits of configuration management to your entire infrastructure.

EventMachine is a library for Ruby, C++, and Java programs. It provides event-driven I/O using the Reactor pattern.