My parents always bring me some unshelled sunflower seeds from Ukraine when they come and visit. e all sit down to have 'a few seeds' and end up still there hours later! You literally cannot stop doing it.
Here in the UK one can't get the unshelled stuff as easily, but you can get the already shelled seeds.
Toast them in a dry frying pan and just eat by handfuls. (It only takes 5-10 minutes to roast on a low heat, but make sure you keep turning them, as they burn easily).
It is not as satisfying as shelling and eating, but still tastes amazing. And you kids would love them too!