EventMachine implements a fast, single-threaded engine for arbitrary network communications. It's extremely easy to use in Ruby. EventMachine wraps all interactions with IP sockets, allowing programs to concentrate on the implementation of network protocols. It can be used to create both network servers and clients. To create a server or client, a Ruby program only needs to specify the IP address and port, and provide a Module that implements the communications protocol. Implementations of several standard network protocols are provided with the package, primarily to serve as examples. The real goal of EventMachine is to enable programs to easily interface with other programs using TCP/IP, especially if custom protocols are required. The present alternative version 'eventmachine-with-ipv6' contains some crucial fixes for datagrams (UDP) and IPv6 developed since 2010 by Carsten Bormann and Iñaki Baz Castillo. This is needed for many applications in 2012, but might detract from the stability achieved for other typical uses of the base eventmachine. It is otherwise identical with base eventmachine. Install either base eventmachine or this version eventmachine-with-ipv6. If you have installed both, use gem 'eventmachine-with-ipv6' before require 'eventmachine' Alternatively use Bundler and write this in your gemfile: gem "eventmachine", :git => "git://github.com/cabo/eventmachine" Please send all bugs in this version to https://github.com/cabo/eventmachine/issues