I label each table (you could use groups of desks, too) with a day of the week, so that we have a Monday table, a Tuesday table, etc. Then on the day of their table, the students do all the 'extras' that in the past I used charts to organize. For example, they use the computers at recess or free time. They read their journal stories to the class. They use games or manipulatives that are limited in number. You can add anything that needs to be charted. I also like to add responsibilities, like helping sharpen pencils or tidying up the room. It helps demonstrate the idea that along with privilege goes responsibility.