I've blogged about my desire to sound less like Charlie Brown's teacher before. As part of that, I am using sounds to signal transitions. I squeak my little squid when the kids have 2 minutes left to check out books. I blow my train whistle when it is time to line up to leave. I use the noise maker to get the class quiet. I no longer have to screech and yell and repeat my self 900 times! It is like Pavlov and his dog. I make a noise and they move! It. Is. Awesome.