From the coderetreat.org website:
Coderetreat is a day-long, intensive practice event, focusing on the fundamentals of software development and design. By providing developers the opportunity to take part in focused practice away from the pressures of 'getting things done', the coderetreat format has proven itself to be a highly effective means of skill improvement.
This year, the Global Day of Coderetreat is happening on December 8. It sounds cool and fun, and of course, Java Champions and Java developers around the world are involved. Here's a small sampling:
You can go to http://globalday.coderetreat.org/ to look up events near you. It's a great opportunity to practice your craft.
Here's a video from an event last year to get a flavor: