In addition to knowing Java, I have decided to start learning other languages. There are a bunch out there, so I decided to stick to languages that run on the JVM. In particular, I will stick to languages that are indigenous to the JVM, like Groovy or Scala, as opposed to languages that have been ported to the JVM like Ruby or Python.
I was in Texas recently, and someone asked for volunteers for help with a Grails project. I gave him my card, and he sent me a link to the project and a link to an online book about Grails. So I am now learning Groovy.
I have been attending the Chicago Groovy User Group meetings over the past few months, and I think that this Groovy language is a good thing to get into. They said the Midwest seems to be the center of the action for Groovy in the USA. One of the speakers was an author well-known in the Groovy community who lives in Saint Louis, the big GR8 Groovy conference was a few months ago in Minneapolis, and there are some decent-sized Groovy groups in Chicago, Madison and Milwaukee. So it seems like there is a Groovy Crescent in the Midwest.