If you are trying to learn groovy and grails like me you should visit http://groovyblogs.org . Really nice aggregator for grails and groovy blogs and posts.

But the most important part this site is, it is open-source !!!

thanks to Glen Smith, you can browse and download its source from the SVN.

http://code.google.com/p/groovyblogs/

Once you download the project you can see a real world example of grails. You can see some good practices and external api usage from grails.

External API’s used:

• charts  (jfreechart)
• RSS reader and writer (rome feed api)
• task scheduling  (quartz)
• event queues (jms-activemq)
• auth
• text indexing (lucene)
• custom taglib
• xml-rpc (groovy-xmlrpc)

Related posts:

1. Is Grails too much Groovy ?
2. Grails Days 1: GORM-CRUD
3. Quartz Concurrent Job execution-StatefulJob
4. Runtime Java Stack
5. Grails Productivity Tip: Depend on Your Plugin