Canon has crammed 120 million photosites--13,280x9,184 pixels--onto a 29.2mm by 20.2mm (APS-H size) sensor. Why? I'm not sure. To use a sensor that dense would require lots of light, so perhaps there are some medical imaging applications that might benefit from the high resolution and be able to supply the controlled illumination.
According to the press release, the sensor can output 9.5fps HD frames from any subsection of the sensor. That might present some cool video possibilities.
(Via Rob Galbraith)