Why Lesson Planet?
It's fun to make a big keyboard out of paper or masking tape depicting a couple of octaves, or just use the piano if there are only a few kids. Place it on the other side of the room and yell out a note. The kids run to the other side to step on it/touch it/play it. With multiple octaves they avoid a pile-up. Also could use a big staff and hit the correct line or space.