Nova is great!
What I really liked about NOVA is that it is very user friendly and all of the videos are very entertaining and engaging. Moreover, there are thousands of videos to watch and they also aren't boring. They are not like the typical National Geographic, insanely boring documentaries. Would totally recommend.
How I Use It
In the classroom I would use this website as a further learning type of deal. I would assign students to watch any video that they might find interesting that pertains to the class material and ask them to write a little bit about it.