I think it's Steve Reich's
Music for 18 Musicians. That's how I would describe that piece anyway.
Here's a clipp:
http://youtube.com/watch?v=CHVMVDhC-UACould also be
Drumming, and (a lot less likely)
Tehillim, which clearly has a text. Come to think of it, I bet it's
Drumming. Not because the people are singing ba-da-ba-da-ba-da all the time, but because that work has so thoroughly entered our collective consciousness.
Edit: it has instruments. They all do. But lots of memorable ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-ba-da-