The final day of the Groovy Grails Exchange had some great sessions as well. I attended Alexandreu Popescu's Groovy and SQL talk, which was a good introduction to all things SQL and database migration. He mentioned several tools I've never worked with, including dbmigrate, DdlUtils, and LiquiBase. Personally, I've always been a database scripts person, but I will definitely look into those tools.
The second session I attended was the Grails UI Extreme Makeover by Glen Smith. That man is hilarious, and also very informative. It was there that I scored my Kualoa (it was a cheap shot, I asked him when his charting plugin would be appearing online). He went into detail about Yahoo UI, which includes lots of nifty widgets like tagclouds, calendar controls, tool tips, in-place editors, and autocompletion.
In the afternoon, Jason Rudolph hosted a Refactotum, which was an introduction into how to work on an open source project without spending your whole life doing it. There was a great back and forth between Scott Davis, Jason, Dierk Koenig, and others on testing strategies. More information on Jason's blog here. Apparently the session led to over six new patches to the Grails framework. Now, if only I could figure out how to get my Ant build to actually call my new Unit Test, I may have a contribution as well!