Charles O Nutter and Tor Norbye just got on stage here, and showed of deploying Mephisto as a WAR-file, and then changing it to add text-to-speech functionality, with a Java library that generates an audio file. The total code they wrote on stage was about 10 lines of Ruby... The power of Java and Ruby together: it's beautiful.
I already knew what they would do, having helped fix many of the issues getting in the way for Mephisto, but it's still incredibly cool. Charles and Tor got several impromptu applauds from the audience too, so I'm pretty sure people think it's neat.
Right now, I'm starting to get curious why people continue to use the term "scripting language". It doesn't seem to fit either Ruby nor Groovy anymore. Oh well. Nitpicking.