Credit: I love 2 Teach (http://ilove2teach.blogspot.com/)
Some other ideas that I have heard:
Teacher: Red Robin! Students: Yum!
Teacher: Class, class, class! Student: Yes, yes, yes! (This one is fun because however the teacher says it, that is how the students should say it. So if the teacher says it really softly or with a British accent then that is how the students need to say it. Or you could even vary the words little. For example the teacher could say, "Classity, class, class" and the students would say, "Yessity, yes, yes")
Teacher: Ladies and gentlemen, boys and girls.... Student: Lads and Lassies!
Things like this can work in older grades. One of my high school classes, which was actually a college class used the "Class, class, class" one and so these can be used for really any grade. However, with the older grades, you may want to change it up every once in a while. In the college class where my teacher used it, the attention grabber didn't work after a while because it got old. I think if you switched it up or had a few different ones that you could use then hopefully the students would continue to answer.
