MailCatcher runs a super simple SMTP server which catches any message sent to it to display in a web interface. Run mailcatcher, set your favourite app to deliver to smtp://127.0.0.1:1025 instead of your default SMTP server, then check out http://127.0.0.1:1080 to see the mail.

MailPot is a simple SMTP server honeypot that will catch emails and store them in S3 and then pop a message into SQS for later processing

Gem has run SMTP server and manipulate letters received. Using the Observer pattern you can subscribe to the event server.

Man-in-the-middle http/https transparent http (CONNECT) proxy over bunch of (unreliable) backends

A simple, beautiful event-based (EventMachine) RPC service and client library

Marso is the beginning of a small lightweight BDD project. Currently, this is just a very simple code sample that only displays a custom message in green or in red depending on the value of a predicate.

RoundRobin handler for ZMQ over EventedMachine

Autoscale your Heroku dynos

Listen to IMAP changes via IMAP idle.

Something small for process management

Dumps filtered stats a single memcached instance to a graphite server

IRC bot to generate memes

Simple CLI-based menu building DSL

Chocopie Game Server Engine by Ruby

Meshchat core implementation written in ruby.

3rd party MeshBlu library for Ruby

A framework for short message paradigms

Cli for Metabase API

metasploit-framework

Utilities for writing application metrics into statsd/graphite