Docile turns any Ruby object into a DSL. Especially useful with the Builder
pattern.
Drydock is a seaworthy DSL for building really powerful command line
applications. The core class is contained in a single .rb file so it's easy to
copy directly into your project. See below for examples.
Dynflow (DYNamic workFLOW) is a workflow engine written in Ruby.
Object Daddy is a library (as well as a Ruby on Rails plugin) designed to
assist in automating testing of large collections of objects, especially webs
of ActiveRecord models. It is a descendent of the "Object Mother" pattern for
creating objects for testing, and is related to the concept of an "object
exemplar" or stereotype. This is a fork of the original object_daddy.
A port of File::ReadBackwards, the Perl module by Uri Guttman,
for reading a file line by line in reverse order. This can
often be helpful for things like log files, where the
interesting information is usually at the end.
Enumerated attributes with I18n and ActiveRecord/Mongoid/MongoMapper support
Ruby library to define equality, equivalency and hash methods automatically.
Errand provides Ruby bindings for RRD functions (via librrd), and a concise DSL
for interacting with RRDs.
Event Bus helps you to setup an event bus for your library.
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.