In the past, I had a 5 y/o boy who DID NOT understand the concept of quiet play.... Grrrr. I finally managed to get through to him that the little ones are sleeeeppping!! So shhhhh.
Anyway, he's gone now and the deal is: Quiet time is from after lunch (12:45ish) until 3pm. The little ones sleep, or stay in the p&p in the bedrooms, anyway. The older ones (don't have any right now, thank goodness) must rest for 45 mins. And then can play QUIETLY, under my supervision but not "involving" me (this is not the time for running games!) until 3. Should they insist on hooting and hollering, they can go back to the designated resting spot until quiet time is over.