I guess I'm lucky to have a little boy who loves to help in the kitchen - he is only 5! He can pretty much help do something with everything I make. But, here are two of his favorites.

He calls it: THE CHICKEN WITH RED SPOTS - Super easy - and since he makes it - he eats it ALL up.
For the 4 of us, I make 2 to 3 chicken breasts, depending on the size. And for this recipe I cut them into strips - AJ just likes them better that way and I think they get more flavor. Or, you can just buy the Chicken Tenders from the butcher.
Take 1 packet of Italian Dressing dry mix. DO NOT MAKE THE DRESSING.
Mix it in a bowl with 1 to 2 TBSP of olive oil. And a little bit of lemon juice or orange juice.
Then, the little ones can brush it on - just like they're painting a picture.

HOMEMADE PIZZA
Quick-Dough fix - if you have a local italian deli - chances are you can get freshly made uncooked dough... and no mess. That's what I do. You can also get fresh mozzarella and pepperoni from their deli... yum yum! Or whatever toppings you prefer.
If you have Trader Joe's - I actually prefer their pizza sauce over the one that my Italian deli makes... find your family's preference.
Yes, a little shopping around, but we think it's worth it.
And I also have to recommend a Pampered Chef pizza stone... or something of the sort.

The kid can usually help roll-out the dough, with help as it can be difficult. But, he loves sprinkling the flour out on the pizza stone, roller and dough... oh yeah - and can't forget on his hands. It does make a little mess, but it's fun... Once the dough is rolled out - the kids can pretty much put all of the toppings on.

INDIVIDUAL PIZZA VARIATION
Cut the dough into halves or thirds - everyone can make their own. How to cook these... BBQ! The kids won't be able to top them, but they have made their own dough - and don't really need as much help with it since they are smaller portions.
Cook one side of the dough briefly on the grill.
Flip over and top while the bottom side cooks. Close the lid for some serious cheese-melting!

Have fun cooking!