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

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

It does cool stuff!