This is the Stockholm local Puppet Hackathon (http://puppetlabs.com/blog/puppethack-online-community-hack-day) (taking place the same day around the world).
We have room for 16 people from 5pm. If you have a burning desire to start earlier (to have time to finish your project) please contact the organizers directly, we can accept a couple of people before 5pm.
If you arriving late you may need to contact the organizers to get into the building. Details will be posted.