CommunityEngine is a free, open-source social network platform for Ruby on Rails applications. Drop it into your new or existing application, and you’ll instantly have all the features of a basic community site.

OpenConferenceWare is an open source web application for events and conferences. This customizable, general-purpose platform provides proposals, sessions, schedules, tracks and more.

A Rails gem to supply a front-end and reporting capability to the Surveyor gem.

admin_assistant is a Rails plugin that automates a lot of features typically needed in admin interfaces.

Because Blogojevich would be too tough to remember. It's a pluggable blogging system for Rails 3.

Clearance-based Rails engine for Software as a Service (Saas) that provides account and project management

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

Rails file manager engine

Provide backend functions for Comable.

Bibliographic record module for Next-L Enju

MTWarden Rails 5.1 engine adds basecamp style user logins (multi-tenant authetication using warden gem) to your ruby on rails application.

Content Manager for RoR

Noodall Rails User Interface Engine. Requires Noodall Core

Build bootstrapped forms with next to no effort

Advanced scaffolding with pagination, ajax, search, namespaces

A Ruby on Rails engine for running ticketing, CRM, and order management. See http://fracturedatlas.github.com/artfully_app/ for the reference implementation

Atreides is an engine providing a evented CMS following a KISS principle

Rails 3 Tumblog Engine

Code clips before they were cool. See README for deployment information

Multi-tenancy with Comable using the Apartment gem