An awesome asynchronous event-driven reactor for Ruby.
Actor-based concurrent object framework for Ruby
Modern concurrency tools including agents, futures, promises, thread pools, supervisors, and more. Inspired by Erlang, Clojure, Scala, Go, Java, JavaScript, and classic concurrency patterns.
Simple evented I/O for Ruby (but please check out Celluloid::IO instead)
EventMachine: fast, simple event-processing library for Ruby programs