Cape Cod Natural History Museum, located right on 6A. Aquarium downstairs, live video of an Osprey nest, displays and a gift shop. Plus it has lots of walking trails, through marsh and wood, even has a bird banding hut and welcomes volunteers!
Nickerson State Park. 2 public kettle ponds for swimming/boating, one of the ponds is dog friendly. Hiking, biking, camping.