Ever notice how your Apple Watch seems to know exactly when you need a little nudge to get moving? Here's the kicker: Apple's about to give you the perfect excuse to lace up those hiking boots and explore the great outdoors. What you need to know: The annual National Parks Apple Watch Activity Challenge launches on August 24, celebrating America's natural treasures Complete any 20-minute workout to earn a limited-edition digital badge and animated stickers for Messages This marks eight years ...