I like one on two, because it requires the students to listen and understand as third-person participants, which is an important language ability.

I think Chris makes the most important point here.

The goal of the businessman is 'I win' - whether it is win-win with his competitors is secondary, and the fact that it is secondary is what produces the endless cycles of violence. But that's why SunZi, on war, applies. It's about individual ego. Meanwhile, the game itself, which is not a game because with games one can choose not to play, rests on the loss incurred by labor, which is systematically in the position of losing vis-a-vis capital - that's why the system works until it doesn't. Hence the contradiction, the class struggle, the movement of history and the self-destruction of the system - which may just take everybody along with it.
Win-lose - ultimately, it's lose-lose; thanks for participating in the effort that has got us this far, but win-win will now have to be something entirely different. May we be saved from the gods (people, nations) and their ego-problems. Enough with the games awready.

It's been fun and it all relates to the OP, but, obviously, all from a million miles away.

No argument with Sun Zi's theories about manipulation, war etc. - but it's interesting that it all starts with the idea of enemies, which seems to put everything on a field of competing individual interests, creating at best allies that can be trusted only conditionally. All highly useful, but I wonder, given the development of technology, whether there isn't a limit to the collective survival value of such thinking, and whether we can't come up with an alternative that is less likely to end in, perhaps universal, catastrophe. Evolutionary theory - theory about 'Nature' and the competition of species - presents absolutely no guarantee, and very little encouragement, of the idea that any species might be able to overcome its logic - but then no other species has ever had the resources of very, very radically, intentionally and collectively (with incredible abilities and possibilities for sophisticated communication) modifying and creating its own environment - the 'nature' of humanity is, in a nutshell, to create culture.

Nothing is written, and nothing is guaranteed.

I'm coll with Hammer's suggestions - creativity is often necessary when following guidelines that aren't working. However, the idea of 'they can waste their time, but why should I waste mine' makes me consider that there is a reason: you are getting paid for it, and if the project of the kids' learning English is a worthwhile one, whether they want to or not - and it's worth considering that it may not be - then I think teaching is a responsibility that shouldn't be ignored.
After all, there is a hell of a lot of worthless, or even negative, activity going on in the world that goes by the name of 'work'.