Pentabarf, open source conference planning

Pentabarf is an out of the box solution for conference organizers. Put the files on your site, tweak a few parameters and you can start focusing on all the other problems like plane tickets, diva speakers management and fake registrants. This (free) application looks amazing. It does not cover all the organizers’ needs but still seems to go a long way. It is maintained by the community behind Berlin’s Chaos Computer Club, so the developers know how to run a conference.