I have to recommend that if you’re itching to do something new, try canoeing. I just did it for the first time today, and it was amazing. If you keep a calm pace, you can really admire a lot of the scenery and appreciate the quiet.
What’s also great is that you don’t even realize you’re exercising until you’re out of the canoe. Of course, there are certain techniques and rules and instructions and the like to it, but once you learn exactly how to do it, really it’s a blast.
And it might enable you to open your mind for a new idea that you may be struggling with in your story. Or it’s just a place to get away from the world for a while–clear your mind. That sort of thing.
Also, try starting a scene that involves a sport you’ve never done before.