Rails for API only applications

AASM - State machines for Ruby classes (plain Ruby, ActiveRecord, Mongoid, NoBrainer, Dynamoid)

Code smell detector for Ruby

Rails authentication with email & password.

Parse and render REST API documents using representers.

A Ruby client for the Salesforce REST API.

Simple, elegant testing for Rails Engines

A rich Ruby modeling layer for Riak, Basho's distributed database

Metrics for ruby - a Ruby implementation of metrics inspired by @coda's JVM metrics for those of us in Ruby land

The Riak client for Ruby.

give anonymous modules and classes names when they are inspected

logstash - logs/event transport, processing, management, search.

Ruby client for the Database.com and Chatter APIs

A rich Ruby client for Riak, Basho's distributed database

Retrieves historical stock & mutual fund quotes

Rails authentication & authorization with email & password.