I just got an email from the Pragmatic Bookstore announcing that my copy of Programming Groovy, by Venkat Subramaniam, has shipped! I have just about finished reading the PDF version but I am still looking forward to having the paper copy in my hands.
I'll try to post a review soon, but I'll give you the short version now:
It's a great book and if you have any interest in Groovy you should buy it right away!