Ian Johnson is the author of Tributary - an open source live-coding environment designed for prototyping data visualizations with D3. He also co-organizes the SF Bay Area d3 Meetup and makes educational D3 videos.
Bay Area D3 and Tributary
In order to build a visualization project, you need data. Tributary allows you to include datasets without incorporating AJAX request. Ian looks a couple examples he's created that demonstrate the inclusion of Reddit's datasets.