You could spray paint them and use wire or clothes pins to post pictures, hang jewelry, they would look great in a flower garden, as a shelf or mounted to your garden house. Tons of ideas.
How about a fence? Love this idea by @Daune | Cottage in the Oaks http://www.hometalk.com/167709/repurposed-shutter-fence
One more: A shutter wall by @Thistlewood http://www.hometalk.com/586640/need-an-easy-fix-for-a-blank-wall-add-a-wall-of-shutters