I call this game, "Tic-Tac-Term!" The kids were divided into two teams, so I drilled them on terminology terms. If they were able to correctly identify the term and tell what it meant, they could place themselves on the tic-tac-term mat in whatever spot they wanted. Of course, we had to keep the mat wet...continuously! :) I tell them to wear a bathing suit everyday so we have this option.
In addition, we played a fun game of Musical Zap! where I quizzed them on notes on the staff. While it wasn't a planned activity, it worked! They are better at reading notes so the goal was accomplished!
When you run a camp, you MUST be flexible and be able to "plan for the unplanned" being able to make changes quickly.