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.

Carry the egg

It's simple - start with any sentence you like. You can write about what you're doing right now, but I usually find this works better with an imaginative story. Write your first sentence. Now take the last word - that's the first word of your next sentence. Take the last word of that sentence - it's the first word of your third sentence. Ad nauseum. How long can you keep it going?

There are a whole bunch of variations to this; the sentence has to end with the first word of the previous, or the fourth word in must be the same in each sentence, etc. It's another one that pulls you away from worrying about whether what you're writing is any good (it probably wont' be, with all that repetition, but that's easily edited out) to thinking about the rules of the game. The restriction shuts your inner editor up, and lets your inner writer be creative.