As students walk in the door hand 10 scrap pieces of paper out at random. Class knows that if they get a piece of paper they have to write a comment about the class topic that day or a question they have. It may be a question a neighbor had. This gives me something to do if i wrap up early or something to start off the next class session. Check for understanding or clarification. It also allows students to ask questions anonymously as I shuffle the papers and others can grab a sheet to add to the stack.