Presentations:

• Groovy Web Services Can't embed that here, unfortunately, but it uses that cool Prezi presentation tool. (Columbus, Ohio, Java Users Group, 9/2009, CT Java Users Group, 9/2009)
• Java and Groovy on Google App Engine (CT Java Users Group, 6/2009)
• How Groovy Helps (NFJS Boston, 9/2008)
• Grails Plugins (NFJS Boston, 9/2008)

Source code:

• Grails Plugin Survey
  • Also available on GitHub as git://github.com/kousen/grails_plugin_survey