You should also consider learning a functional programming language like Scala. It has many of the advantages of Ruby, including a concise syntax, and powerful features like closures. But it compiles to Java class files and and integrate seamlessly into a Java stack, which may make it much easier for your employer to swallow.
Scala isn't dynamically typed, but its "implicit conversion" feature gives many, perhaps even all of the benefits of dynamic typing, while retaining many of the advantages of static typing.
