What is this?

This is what I got when I combined webcam-based gesture recognition with Hakim El Hattab's reveal.js.

It took me a while to write and fine tune the detection algorithms. Even then, the algorithms are only about 80% accurate. You get the gist of it though:

A flick of the hand in mid-air changes the slide.

A two hand flick up or down activates the slide overview.

Tips and troubleshooting in the slides below (you can still use the keyboard or reveal.js's built in controls)