Ronin is a Ruby platform for exploit development and security research. Ronin allows for the rapid development and distribution of code, exploits or payloads over many common Source-Code-Management (SCM) systems.
For more info see the FAQ
Check also ToorCamp: Ronin - A Platform for Publishing and Mayhem
A talk at ToorCamp 2009 discussing Ronin, how it can be used as a Platform for Publishing and Mayhem, given by Postmodern of Sophsec Intrusion Labs.