Today there are conferences for almost every interest, and CMSs are no different. Whether it's a system specific conference like DrupalCon or WordCamp or a general conference like CMSExpo or the Gilbane Conference, there is no lack of opportunity to expand your knowledge of the CMS space.
While the general conferences tend to stay at a high level when talking about a given platform, system-specific conferences can be great for learning about upcoming release features and more advanced functionalities.