At the end of the year the focus isn't quite what it was at the beginning of the year - for both you and the students. So some quick, easy and engaging art activities that keep the creative art muscles stretched is the only way to go to give you some peace of mind while you are starting to clean up the room, order supplies etc.
This first exercise is to have students cut out from a magazine one body part ... foot, head, lips, ear etc. Once glued into their sketchbook they extend the image into something else. I only give them one class and since some students work faster than others, some remain in pencil partially finished while others are more developed. This could easily be stretched out to two days or more and elaborated on. Good one for the substitute teacher also and you could have an envelope filled with body parts which students randomly select. It's a good job to give students when they are finished early - cutting up body parts to fill up that envelope for when you need it. Morbid but they seem to enjoy cutting up magazines and chatting with friends.