one word
So the latest and greatest fun wordie site I found is called one word. It's a great way to get the ol' writerly juices flowing.
Basically, all you do is click go. A word will appear at the top of the screen. You have 60 seconds to write whatever comes to mind. When you're finished, you'll get to see what others wrote. Some of the entries will make you feel like a genius. Others will make you curl into the fetal position and cry for your mama because they're so good. Either way, it's a great exercise to make your writing flow.
It's a ton of fun though. Give it a whirl next time you want to waste time, I mean find excellent writing exercises to share with other authors.