Stop talking, start prototyping. Less action items, more actual items. Bring people together to make things. Hackathons are spreading around the world as a mechanism for rapidly prototyping new creatively- and socially-driven projects. This is the first time in history where, thanks to social media, open source tools and collaboration, and mobile technologies, an idea can be prototyped, iterated, deployed, and scaled in an extremely short time frame. This process will change the way we innovate, and the way our cities look, feel, and act. As IDEO's Tom Kelley argued, "prototyping is a state of mind" - and when large numbers of people adopt this state of mind, we will experience a prototyping revolution. This presentation discusses the experience of Gray Area Foundation for the Arts in producing 10 hackathons in 18 months, on issues ranging from community development to transportation to digital art - and how these short periods of intense collaboration are setting the stage for broader changes in society and the way we work together. This presentation was given at TEDxSoMa in San Francisco for the international day of talks themed under TEDxCity2.0. The full video is available on the TEDx Youtube page here: http://www.youtube.com/watch?v=In_rSS-mJ-8