I haven't actually used Groovy much since, oh, egads, umh, 2004. It was at 1.0b6 and was taking a direction which I both disagreed with and found kind of boring. It was throwing away large chunks of dynamicity for some performance gains as it decided it really wanted to be compiled, after all. Large chunks of the new syntax I also disagreed with so... I wandered away, wishing everyone luck.
Well, funny things can happen in, er, three and a half years, so when a coworker suggested we look at Groovy for solving a problem my initial reaction was "erk, umh, I kind of like our use of JRuby for that" but Groovy wasn't even at 1.0 when last I used it, so it was a pretty unfair reaction. Looking again, it is at 1.5.4! Time to revisit!
After noting that none of my old code parsed, I worked through the tutorial. This isn't the same language I last used. It smells like Perl or PHP more than Ruby, which it rather resembled back then. Overall, my second "first" impression: totally practical, rather ornery. Will dig into it more.