Ruby is a powerful, expressive, and beautiful programming language. But like all programming languages, Ruby makes tradeoffs between the features it supports and those it does not. As a consequence, some people find other programming languages more suitable for a particular problem. However, switching languages is potentially costly and usually requires learning entirely different tool chains. What if we could keep Ruby and only use a different language where it is most needed for specific parts of an application? This talk will introduce Rubinius and focus on features of the platform that make it simple to implement other programming languages.