CitConf is a focused conference on Continuous Integration Testing, and takes place three time a year around the globe. This years North American location will be Fort Worth, Texas, on April 27th and 28th.
CitConf uses the OpenSpaces format which was pioneered by Bruce Eckels as a way to lower the management overhead of typical conferences. At CodeMash I joined Bruce and some others in a OpenSpace format session, and as long as the group is small, and interested it works quite well. Since CitConf is capped at 100 people, it seems like an entire OpenSpaces format conference would work.
At any rate, the conference is FREE, as most of the costs are either borne by sponsors or eliminated via the OpenSpaces format.