Writing games are tricks, exercises, things to try to get your writing brain in the mood. I find them useful when a story's giving me trouble - I can't think of a way out of the corner, or I can't think of a corner to get into, or I'm just not feeling in the right mood to write that story - as well as generating new ideas, and just keeping my writing-mind in shape. And on the plus side, they're usually fun to try, and you can end up with the germs of some great little stories.

Hey, that's my line

Take a scene with two characters you've already written. If you don't have one handy, take a scene from a novel, or even a film, but make sure it's one you know well. Rewrite the scene, swapping the characters' arguments. That is, if John wants to go west in the original, and Betty wants to stay put, have John argue to stay put, and Betty yearn to venture west.

The trick is, what works as motivations for one character probably won't ring true to the other. If John wants to go west because that's where his brother went, Betty can't just have a brother spring up out of nowhere - she needs her own reason to go west. Similarly, John's going to need a more pressing reason to stay rather than follow his kin.

The work here is in re-exploring the characters to find motivations that ring true, but still make them do what you want.