The entire Groovy website is stored in this wiki
The home page is called Home then the navigation links on the left are on a magic page called Navigation and the top right navigation links are on a magic page called QuickLinks.
Hopefully now anyone can contribute to the documentation.
If you ever edit a page and wonder why its not yet been updated on the http://groovy.codehaus.org/ site well it could be cached. To view a latest greatest page just add the 'refresh=1' to your URL. e.g.