If you are lucky your four sons will spend copious amounts of time outdoors in all sorts of weather, in all sorts of seasons, and even in the dark if they are so included and you remembered to stock their Christmas stockings with flashlights.
What will they do out there?
They will spend 95% of the time chasing each other around with sticks.
I once found a handmade sign in our yard that read, "sticks rule." Couldn't argue with that.
The other 5% of the time they'll spend strewing about the yard all the outdoor toys that they don't actually play with. If they can reach a hose and turn it on they'll make mud pies which they'll stir up with their sticks.
If they're old enough to have pocket knives they'll whittle their sticks into points in order to up the chances of putting someone's eye out.
Outdoors is a great place for your kids to be because when they scream they'll just annoy the neighbors and not you.
They might even wander into the neighbor's yard and then, like illegal aliens crossing the boarder, they'll be able to stay and live at their house instead of yours.