This is a great event for either the whole school, Houses, or individual classrooms. Teachers decide on a theme and have students create their own interpretation of it.
Once all artwork is complete, students submit their masterpieces for voting. In order to make it fair, different grade levels or classrooms would vote on their own to avoid favoritism and give everyone a fair shot! Categories for voting could include the most unique, most creative, the cutest, etc. and the winners could receive a prize.
Then give LiveSchool points to the winning House or students.