DEFCON is one of the oldest hacker conventions around, and also one of the largest. DEFCON is what you make of it.
There are several resources that will give you an idea of what DEFCON is all about.
DEFCON Press: through the prism of the media
DEFCON Pics: visual evidence, thousands of pictures, some NSFW
DEFCON Groups: Local groups that meet
DEFCON Media archives: Speeches from DC 1 to the present, captured
Google: always a good research starting point
I am sad to say that I cant make it this time. Perhaps next year we could organize some of us from the forum to go as a small group. Those events are more enjoyable as a group than solo. Maybe we could represent EH-Net?