I hadn't until we moved here last year. I fell in love instantly; lots of trees and mountains. But don't take my word for it, check out the pictures below of some of the outdoor activities my family enjoyed in the Berkshires last fall.
Natural Bridge State Park - Beautiful trails and very family friendly. Lots of good fences; you'll see why they are needed below. Perfect for a quick afternoon trip.
Sweet Brook Farms Hay Rides - Not only are there hay rides, but alpacas and maple products.
The Clark Art Institute Trails - The museum is free most of the year and has a good kids space. The trails are rated easy to somewhat difficult and offer beautiful views of Williamstown.