BarCampSeattle is happening this coming weekend on June 14th and 15th at the Adobe Conference Center. BarCamp is going to be different than the SeattleMindCamp which was delayed and seems to be working on a new location/venue.
Last month the BarCampPortland was a great experience, with many people gathering in CubeSpace and exploring different topics. As an unconference, you get out of the conference, based on what you bring to the conference. Being willing to bring some idea to talk about and share can make all the difference.
The topics have ranged widely from detailed discussions of Drupal or of the semantice of Rails, to things as far ranging as knitting, Women in Science Fiction and PeakOil discussions.
Seattle Barcamp is using Pathable.com to register people for the event
Take a friend or two with you when you go to the event and bring something interesting to talk about. The depth of skills in the room has impressed me, I think it will impress you too.