Live streaming video via my Apple TV from the Okeanos Explorer, a NOAA research ship now exploring the Mariana Trench. Right now, its ROV is collecting coral at a depth of about 1800 m. Yesterday they were at nearly 6000 m below the surface!
Not only is there breathtaking HD video, but collaborating scientists both onboard and ashore provide a live running commentary. This is a must-see for science nerds!
Search YouTube for the oceanexplorergov channel. Watch Camera 1.