One of my favorites, lately, is popcorn for an afternoon snack. Something about all that popping followed by crunchy eating seems to calm both the boys. We make our popcorn on the stovetop, using coconut oil, in the cast iron wok. I find in the wok, I can get away without the violent pot/pan shaking. Also, the boys love watching the kernels pop through the glass lid.
It's possible popcorn got a bad reputation as a snack sometime in the past 20 years; but I can find much bigger evils than popcorn in the boys' diets. And I'm picking my battles carefully these days.