You must absolutely listen to this TED Talk by Eric Whitacre, although it's more a TED song. He's a contemporary composer who has created a virtual choir through Youtube that sings his wonderful work. If you click on the link you will have a chance to hear a premiere of "Sleep" sung by virtual choir 2.0 as well as some excerpts from the first 1.0 virtual choir singing Lux Aurumque, another of Eric's transcendant compositions.
The Sleep visuals are really, really interesting — a kind of "mind-map" of over 2000 people singing in virtual space.
I'm sure he won't mind if I publish this image of the cover of his Lux Aurumque album, since I couldn't find any images of the spacey mindmap…!