ActiveModel session

Allow using a Shotgun site as a DB for Active Model objects.

A simple gem for easily using the state design pattern in Rails.

Provides subset validation for serialized arrays or sets in Active Record

Typed store for active records json/hstore columns

Allow to store ActiveModel validations in ORM.

Validate commonly used attributes easily with ActiveValidation.

Contains validators for date and time values, type checking.

ActiveVector provide a way to use Vector data structure in Ruby

ActiveModel style WePay interface.

Activity Provider for store data of education in LRS (Learning Record Store) based on xAPI specification https://github.com/adlnet/xAPI-Spec/blob/master/xAPI.md

Activity Streams system by Fotonauts.

Actn.io DB

acts_as_api library adjusted to support sequel models

Rails 3 gem to treat an attribute as a decimal (getting and setting floating-point values) but storing it as an integer in the database (useful for prices and other precision-needed attributes like money).

Use dynamic attributes in your classes

Seamlessly integrates Java's Executor framework with Ruby on Rails

Acts as a Parameter Object cf. Refactoring: Ruby Edition

Description of ActsAsPluggable.

Sanitizable concern to sanitize attributes the way you like