Act-as-Buddy is a gem to allow any model to implement self relation. For eg: the friendships of a user can be implemented easily by self relation technique of act_as_buddy. Any Model can be buddied or lopped on to itself. Main uses would be for Users create friends etc.. Eg: User has many friends and friends are members of users table itself. This is expected to be heavily useful in social networking domain.

Redirect all SELECT queries to a separate connection within a block

This gem adds support to the ActiveRecord (3.x and 4.x) for composite types.

Entity-attribute-value model (EAV) is a data model that is used in circumstances where the number of attributes (properties, parameters) that can be used to describe a thing (an "entity" or "object") is potentially very vast, but the number that will actually apply to a given entity is relatively modest.

Acts as kaltura

ActiveRecord extension that provides revision support so that history can be tracked and changes can be reverted. Emphasis for this plugin versus similar ones is including associations, saving on storage, and extensibility of the model.

ActiveRecord extension that serializes destroyed records into a trash table from which they can be restored. This is intended to reduce the risk of users misusing your application's delete function and losing data.

A Rails admin interface generator. Theme stolen from Redmine. Similar to web-app-theme but better ;).

A simple gem to find age using date of birth - works for leap years also

Acceptance test framework for ZeroMQ applications. Includes some cucumber helpers.

Highly configurable dumb auto-scaler for managing unicorn web servers

A specialized Amazon AWS gem for finding Album Art running on top of the 'sucker' gem

Ruby interface to the AMEE carbon calculator

Ruby bindings for the Android SDK adb command.

Annotate Sequel models

apirunner is a testsuite to query your RESTful JSON API and match response with your defined expectations

A clean and simple way to manage your application's per-environment constants

Appjam is iOS code repository, including framework, snippet, generators, etc.

Facilitates float comparisons in mocks

Ruby client for ArangoDB