Central - an interesting resque & sinatra-boilerplate based cluster management system!
Most of the orchestration platforms out there are java based, or just a bit ugly to set up. This project strives to do it The Ruby Way, and offer more flexibility in the types of actions that can occur.
If you want to know about the base framework we used, check out their github project: https://github.com/l3ck/sinatra-boilerplate