They're never bored with even the simplest of these games. They never act like they're too old for them. The opposite is true. They go nuts. They're STARVING for these games.
Music is made up of two elements: Work and play. We do a certain amount of work to get to a state where we can play. Some music takes an immense amount of work before the musicians can play (Schoenberg's String Quartets). Other music takes almost no work, and the results are often more fun than interesting (middle-school rhythm circles).
In our schools I think it's very fashionable to show off how hard we're working. We give concerts designed to show how hard the chorus worked. We judge our choruses on how hard they've worked to get to this point. Nothing wrong with that...the harder the work, the greater the reward.
Do we ever lose sight of the reward? When we're in concert, are we saying that the work is done and now we're playing? The audience doesn't want to watch us work! If we can't play in concert, but can only work, what are we saying about our subject? Are we competing with math all the time, so we have to show our work?
If we are in fact obligated to show how hard we're working in chorus, to ourselves and to our audience, so that our subject is treated with the dignity it deserves, then I think it wise that we also make sure there are times in our classes when we get to play. The students need it. They want to experience what it means to have fun when they are making music, because that's what they see in the best performers.
We want our students to know that the best music takes work. We also want them to understand the reward for doing that work. If either half is missing, it's not music.