We launched Deploy Button for RailsRumble 2012. Our team Lizi won 1st place as chosen by the public, and 3rd place as chosen by the judges. In the week since launch, Deploy Button received over 15k uniques, and 6k users have triggered a deploy.
The idea was a simple button you could press whenever you wanted to deploy your site. Worked by pulling your code off github and pushing to any server.
The key feature was that it could be called via webhook, so it enabled really simple continuous deployment (particularly using for a staging environment).