Blogs, articles etc.
The grails group on Facebook, also occasionally provide nice discussions
Swagger for JAX-RS Plugin Adds Swagger support to document REST APIs of projects that use the JAX-RS (JSR 311) plugin
MongoDB Create-Drop Provides applications using MongoDB with the ability to mimic the "create-drop" behaviour available for other databases.
Glyph Icons Plugin Bundles free icons from http://glyphicons.com
Conferences and meetups