Joining role playing games online can be a fantastic exercise for any writer. Unlike traditional pen and paper role playing games, online versions require you to write the actions, thoughts and decisions of your character through email corespondence with other player's characters. Not only is this a great way to push yourself to write on a daily basis, it is also a good way to practise flexibility in your writing as you react to an ongoing story that more often than not unfolds according to what you write yourself. A great exercise that can be quite fun too.