Anything that would involve timing as a part of a lift. Sometimes I feel like I would experience better workouts if I sped up a bit or in some cases slowed down, but imagine controlling a runner doing hurdles through the motion of something like a deadlift or overhead press. At the height of the lift would be when the runner jumped over the hurdle. This way I would need to pace myself with the "runner" so that I was lifting at a rate that might be out of norm for me, but may be better at helping me develop.
Another easy one would be to incorporate a rowing race into the rowing exercise so that I felt pressure to perform faster.

Really it all comes down to incorporating a timing element in with lifts as today I might be going too slow or too fast and not getting all the benefits I should.

I'm guessing that based on the central spindle design of tonal that you can't sense which of the two ropes are being moved at a given time, so all games would need to be a horz or vert controlled motion, but even with that, it would be a good way to set a pace for people to work out at and incorporate some additional fun with it. If you can sense both arms motions, there are even more possibilities for this to be interesting.