It will be interesting to see this evolve. Their aim is create a scripting language that is Java-like but incorporates favorite language features from the dynamically typed language world as well.
I for one applaud the focus on blocks, closures and tuple manipulation. The inclusion of a meta-data facility in groovy will provide for some powerful code.
Their goals include integration with existing java classes which positions Groovy nicely for scripting and unit testing.
Keep an eye on groovy.