Here's some links in no particular order and for no particular reason...
Groovy + Ant = GANT - Guillec treats us to a Venkat inspired tour of Gant.
Practically Groovy: Of MOPs and mini-languages - an Andrew Glover classic on MOP and a good read. I dusted it off in recently to refresh my memory.
Getting Groovy with with - Jeff Brown drops some Groovy moves on us. Always one for the slick trick that Jeff Brown.
How to write a Spelling Corrector - Rael Cunha shows us a reimplementation of the Norvig spelling corrector. Rael's post is really on Java but still shows some Groovy. Is there a Groovier version?
Some JavaFX, Java, Groovy Examples - Andres Almiray blows minds with his meta-hot JavaFX/Groovy cross over code. Along with his follow up it's a fantastic example of JVM polyglot programming.
... and now for something completely different.