These are tickets to give to students that are working hard during centers. I like to give them two (one to keep in the classroom to trade in for prizes or treat later, and the other to take home to show their parents.)
In my classroom as part of our classroom jobs I pick someone to be the center watcher or observer. During center time they are to keep their eyes open for one boy and one girl they see that are on task. I also have a safari hat and kid binoculars they wear if they choose. At the end of centers they tell who they picked and give them a center ticket. I have a poster made with envelopes attached for each student for students to keep track of their tickets. This is great especially if you have a safari theme room.