Over at his blog, Fr Z recounts his attendance at a concert of music written for the Sarum Use "so beautiful it hurt". He includes a video of the performance which you ought to warch because it is sublime, but I want to draw your attention to something else.
If you watch the screen at 56:19 or 58:30 you will see Fr Z demonstrating what actuosa participatio really is. It doesn't mean that he has to sing, or conduct, or in fact do anything physical at all. By paying attention to the action of those whose job it is to do things, he is able to join himself completely to what they produce.
The reward is probably the widest grin in New York that evening!