Here are the Defcon 20 badges (pics borrowed from the Parallax website). Parallax had the awesome job of making them this year, and they did an amazing job. You read all about it on their website
Each of the badges are issued to the type of attendee you are. I personally think that other than the Uber (black) the Goons (red) and the Press (blue/yellow) had the best badges. They have an infra red sensor that can dock with other badges. According to l057, by completing on docking all the badge types, it'll reveal an easter egg. To check what you have to far, you'll have to plug your badge to the Parallax Serial Terminal at 57,600 BPS to see who you have encountered. You can see my badge results below. I thought I was able to pair with an artist but it obviously did not dock. The Uber (contest winners) holders were pretty hard to locate since they do not give those out until the end of the con. Most of them just rush to the airport...
The Human badges also come in multiple variations. I'm not sure how many there were. According to DT, they made 16,500 badges this year. The rough estimate for attendees was about 15,000. So they had extra Human badges after the con. He has announced that they will be selling the badges for $40 each.
