I teach some classes with many absentees. To put the responsibility on the absent student, I keep a file folder for each class by the door. When I hand out a ditto to the class, I ask one student to take extra copies for the absentees. She or he puts their names and the date on the top of the sheet, and puts it in the folder. The students know that if they have been out, they should check their class' file folder when they come in the next day. This method is also a good way for me to have work ready should a request come from the office for work to be sent home for a long-term absence.