impress.js is a presentation framework that makes use of the power of CSS3 transforms and transitions in modern browsers. You can create stunning visualizations by positioning, rotating and scaling anything on an infinite canvas.
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There are actually some GUIs being developed to make Impress.js presentations these days. This one seems to be the furthest along: http://tantaman.github.com/Strut/client/web/index.html
video: http://www.youtube.com/watch?v=zA5s8wwme44