A few years ago, my dude and I visited the Sistine Chapel. In order to get people to be quiet and respectful, there were overseers in the four corners of the room who would randomly call out "Silencio!" while clapping their hands.
I plan on immersing myself in the MS3 until my copy of HP7 shows up. If you read ahead or know how it ends, I have one thing to say. "SILENCIO!" (Clap! Clap!)