Thread: Prezi.com

https://github.com/bartaz/impress.js (source code)

impress.js also works as its based on the prezi except its created with css, html, and javascript. I've used it for a couple presentations its pretty good if you know a bit about web development. I has its advantages and disadvantages to prezi but mainly its free. The free edition is too basic and I wouldn't use it enough to justify the price. Its still pretty neat though.