Everyone wears "multiplication name tags" throughout the day. You always call each other by their "name". This is Mr. 32.--I LOVE this! Could do it all week to get gobs of practice in. Could do this for addition/subtraction or place value.
Give me five is a great way to get students attention with out yelling. It is simple and something the students will understand. Discussing and posting this up on the wall will help the students to know what is expected of them.