For a core music class for grades 5 and 6 (30 minutes). I did this with my 5's and they loved it although you'd have to explain what abstract means. I'm going to do this twice and pull the second mark on the report cards.
Instructions: Pick 4 instrumental songs to play to the class. As the song plays (about 30-60 seconds), the students use colour and lines to draw their 'feelings'. On the back of each picture is a very short reflection that they write after each song. Included is a rubric using I can statements.
It's a simple task that could be extended in many ways and can be used as an assessment. It's pretty fun to mark.