RuboCop has many breaking changes between releases. This tool migrates your RuboCop config, making updating RuboCop easier.

Let ActiveRecord serialize and cast your UUIDs to and from binary columns in your database.

The New Relic Plugin Gem is used to send plugin data to New Relic from non-application sources.

OmniAuth strategy for Hubspot (borrowed heavily from @kmrshntr)

List leaderboards, post scores, etc.

Ruby client for Google Picasa API

A simple Rack middleware for checking app health.

The Plezi.io Ruby Framework for real time web applications.

Polyphony-http: Polyphonic HTTP for Ruby

As of OSX 10.9 Safari can receive push notifications when it is closed.

Quality is a tool that runs quality checks on your code using community tools, and makes sure your numbers don't get any worse over time. Just add 'rake quality' as part of your Continuous Integration

Rack middleware for serving static gzipped assets generated by the Rails asset pipeline

Ruby extension for ZeroMQ (ZMQ) using CZMQ - High-level C Binding for ØMQ (http://czmq.zeromq.org)

Refrigerator freezes all core classes. It is designed to be used in production, to make sure that none of the core classes are modified at runtime. It can also be used to check libraries to make sure that they don't make unexpected modifications/monkey patches to core classes.

Auto-reload require files or local gems without restarting server during Rails development.

A Resque plugin. Adds locking, with optional timeout/deadlock handling to resque jobs. Using a `lock_timeout` allows you to re-acquire the lock should your worker fail, crash, or is otherwise unable to relase the lock. i.e. Your server unexpectedly looses power. Very handy for jobs that are recurring or may be retried.

Optimally distribute and run RSpec suites among parallel workers; for faster CI builds

Run RuboCop against your Markdown files to make sure that code examples follow style guidelines.

Map helper functions for Sass 3.3 Maps including get-deep and set/set-deep

Schmooze allows a Ruby library writer to succintly interoperate between Ruby and JavaScript code. It has a clever DSL to make this possible.