For a few years now the PhoneGap team have been running a one day conference called PhoneGap Day. This is easily one of my favorite conferences. It has a very laid back vibe. The sessions are short and sweet (20 minutes or so a pop). The schwag is actually useful. Out of all the conferences I attend, this one just feels the most relaxed, fun, and educational as well.
This year PhoneGap Day will be held in San Francisco on October 24th and Berlin on September 26th. As before, there will be full day workshops on the day before. For more information, visit the web page: http://pgday.phonegap.com/
Want to speak? The call for speakers is open as well. I've submitted one topic and plan on submitting another.