I've never had a problem with the first 5 minutes of class. I greet each kid at the door when they walk in and encourage them to go get their work out. In fact my old room (I am moving) was so small that they ran to get to class before anyone else to get the "good" supplies first! I also make sure that where they 'store' the work (drawers, or drying rack) is RIGHT by the door so they get their work out as they walk by it. I would say that generally everyone is on task BEFORE the bell rings! Of course this has to be carefully 'trained' into them!