I enjoyed a really great Gr8Conf 2012 in Copenhagen. I presented four sessions this year. As you might know I tend not to have any slides, but love to do live coding. Which means you must have been there to be able see what is covered. But for the university session Getting Groovy I have written a 60+ page document with text and code samples. Also there is a slide deck for this session.
For the Grails Hidden Gems session I have pushed the code I have written (and wanted to have written during the session, but one-hour is not that much if you want to show all cool Grails stuff) to GitHub. The Groovy Hidden Gems was also live coding and unfortunately I didn't save or record the code. The code I have written in my last session Gradle Hidden Gems is also on GitHub.