My favourite Groovy/Java/IntelliJ web presenter, Vaclav Pech, has a short 20min Parleys talk on using Groovy with IntelliJ.
What I found neat was IntelliJ’s ability to take a Java class, rename it as a Groovy one, then refactor all the annonymous inner classes. I also learnt about the capabilities of Groovy, the part where a class gets defined as a Map. Wonderful stuff.
Also neat, was showing how refactorings apply not only to Groovy and Java, but also to Scala code in the same project.