The kids at school are usually called to attention in a military fashion. If you've taken Taekwondo, you might've heard the phrase, "Chariot!" I'm not sure, but it seems to be the equivalent of, "Attention." Kids should stand (or sit, depending on the circumstances) with hands at their sides and face forward. Usually, every chanting request made by the teacher is followed by a chanting response from the students. With my first graders, I say, "Look at me! Look at me!" The students must respond, "Look at you! Look at you!" There are and movements for this chant.
Some other chants and gestures the kids must do include putting their hands on their head, closing their eyes, or clapping a certain number of times. During assemblies, the military-style chants are used to get everyone's attention. Some days, I feel like teaching my students the English equivalents. I suspect they already know, "Attention!"
'Til next time,