FOSDEM is also a pentabarf user. I've heard that they are experimenting with frab for the lightning talks for 2013. A couple of talks have recently been confirmed, no doubt some people will find this keynote interesting: https://fosdem.org/2013/schedule/event/keynote_keeper_of_secrets/ and this track also looks like it has some interesting content: https://fosdem.org/2013/schedule/track/open_source_challenges/