In my classroom, I liked to have music playing when the students came in. It was usually classical and the students seemed to enjoy it–one student was especially fond of Mozart. From some recent tweets, I discovered several sites with a different take on music videos—they are related to science topics.
Frank Gregorio, a science teacher from Virginia, posts videos on the Gregs Educational site.   Spectacular graphics and music are part of these “trailers” that can be used as introductions to class topics (or just because they’re beautiful). They’re less than 5 minutes long and include a brief summary. Most have some text overlay but no narration. The videos can be downloaded from the site. I’m going to use a few at the beginning of some workshops I’m doing.
I’d love to know how the producer of The Symphony of Science videos does it.  The narration is mixed so that it sounds like the scientists (such as Neil DeGrasse Tyson, Carl Sagan, or Stephen Hawking) are “singing.” The lyrics are provided along with the sources of the information. I can watch these over and over. I first became familiar with this project through a remix of Mr. Rogers.
Science Bulletins are documentaries from the American Museum of Natural History that feature stories, data visualizations, and news updates on discoveries and research in astrophysics, Earth science, biodiversity, and evolution. They also feature music and beautiful graphics.
 
Graphic: http://vimeo.com/channels/114270