An easy-to-use Dropbox client with fine-grained control over syncs. Think of it as halfway point between the developer API and a normal client, which gives you control over what and when Dropbox syncs but handles all the details.

deck.js (http://imakewebthings.github.com/deck.js) is a JavaScript library for building slide presentations using HTML 5. deck.rb (http://github.com/alexch/deck.rb) builds on top of deck.js, adding some features and letting you focus on your slides, not the HTML infrastructure.

Deploy smart, not hard.

Ruby wrapper for Lucene Solr

A universal interface to grab contact list information from various providers including Yahoo, AOL, Gmail, Hotmail, and Plaxo. Now supporting Ruby 1.9.

EmailHunter is a minimalistic Ruby wrapper for the Hunter.io API. It provides a straightforward interface to integrate Hunter.io's email discovery capabilities into your sales and marketing workflows.

Easy online payments with eWAY and the eWAY Rapid Ruby gem.

Simple Money handling for your ruby app – ISO4217-compatible Currency instantiation, conversion, string formatting and more via an intuitive DSL: 1.in(:usd).to(:eur)

Engine Yard Core API Ruby Client

facebook_oauth is a Ruby client library for the Facebook OAuth Graph API

Fault-tolerance tools for ruby based on circuit-breakers

Ruby driver for FaunaDB.

Views Are Code: use all the power of Ruby to build views in your own language.

Fuel SDK for Ruby

Gas is a utility to keep track of your git authors. Add them to gas and switch at any time. Great if you use one author at work and one at home or if you are doing pair programming. Includes SSH support.

Geocodio is a geocoding service that aims to fill a void in the community by allowing developers to geocode large amounts of addresses without worrying about daily limits and high costs.

Ponies

A description of your project

Ruby wrapper to the Google AJAX API REST interfaces(Feeds, Language and Search).

Google URL Shortener is a library to compress and expand goo.gl URL's. It also provides an interface to review the analytics of a short URL.