Resque
Ruby library for creating background jobs and processing them
.... Resque is heavily inspired by DelayedJob (which rocks) and comprises three parts, a Ruby library for creating, querying, and processing jobs, a Rake task for starting a worker which processes jobs, a Sinatra app for monitoring queues, jobs, and workers. Resque workers can be distributed between multiple machines, support priorities, are resilient to memory bloat / "leaks," are optimized for REE (but work on MRI and JRuby), tell you what they're doing, and expect failure.