I just had the best idea ever. If anyone who can do something about it is reading this, feel free to do something about it, but if it makes lots of money please send me a token of your appreciation.
Here it is: a treadmill that connects to the PC. In order to make your character move in the game you have to walk. If you want to run or ride an animal or vehicle, you have to run! So all those long distances covered in The World of Warcraft and other games will actually translate to real exercise! And it will also make sure you don't play the game too much as you will eventually get really tired.
Unless of course you get into a crazy battle when you're try to jump around like crazy and you end up being thrown off the machine and breaking your neck. If that happens, don't sue me- sue the idiots who made the machine. I have absolutely nothing to do with it!