For the upcoming BBC nature series "South Pacific," filmmakers rigged a TyphoonHD4 to shoot above and underwater HD in gorgeous slow motion.
(Be sure to watch that clip in HD.)
Shooting a frame rate 20x the speed of normal HD (I'm assuming that's somewhere around 480fps if the standard HD cam shoots at 24fps), this camera/documentary was apparently the first to capture the underwater spiraling vortices of huge waves at such incredible quality. Cameraman/technician Rudi Diesel calls one moment in this clip "probably the best shot" of his life.
I can't imagine the intensity of shooting surfers riding 12-foot waves from a vantage point directly beneath the action. But in slow motion, the scene is incredibly serene. [BBC]