I have high hopes for Duby becoming a viable alternative to javac! Since it uses the native typesystem and doesn't require a runtime, it is 'just' a Ruby-like syntax for writing code for the JVM.
A lot of people are jumping on board to use Clujure, yet it doesn't use the native typesystem and does require a runtime? (I know little about clojure, I'm just guessing here, please correct me if I'm wrong.) So why would people not jump on board with using a Ruby that sat on top of the JVM with non native typesystem and requires the run time?
Clojure solves a whole set of problems at the language level that imperative languages like Ruby can't easily address: Simple concurrent programming (http://clojure.org/concurrent_programming).
FWIW, Duby is not "done" or "ready" yet, but it's moving along. The promise of a static-typed language with all the expressive power of Ruby (or at least, Ruby's syntax), but the performance of Java and no runtime library is very compelling to me.
Is Duby really ready for production yet? The twitter posts referenced are blocked, but it appears at least someone is using it for production stuff. Anyone else?
I should have made it clear that we opted not to use Duby for this project because a) the Java version was almost done and b) it still seems immature. Android development depends on a prerelease version of jRuby, so I wouldn't consider it production ready.