We all know about high dynamic range (HDR) imagery due, in part, to the examples you can find on Flickr. This image I nicked from Wikipedia shows how three bracketed shots are combined into a composite image where you have all the details in both the blacks and whites that couldn't be captured in a single image.
So how could you achieve this with moving images? Have an ultra high frame rate camera where you can capture three frames sequentially with a rotating set of ND filters? Maybe, but the focus and effect are somewhat spoiled by rapid moving parts of the image. The guys at Soviet Montage have a system where they use a beam-splitter to feed the same image into two 5D Mk2s (one of which has 24dBs of attenuation - that's four stops for non-video people!).
I think it looks very engaging. Kind of like a moving old-master. For my money this is much more engaging than 3D on TV with none of the problems that 3D at home have.