In simple layman terms: High Dynamic Range. The ability to take a
series of different exposures of the same scene and combining them in
post processing so basically all the image is properly exposed.
HDR's are created by taking multiple Low Dynamic Range (single shot images from any camera ) shots exposed for the highlights, mid-tones and shadows seperately and then merged into a single 32-bit image which has a dynamic range up to 14-15 stops.
Nearly all 32-bit images are impossible to view on a monitor or print out so you need to compress the tonal range down to 8 or 16bit by tone mapping.
This October and November, it's going to be HDR's.
Check out all the photos.