Are you wanting to make the food more healthy, or just trying to come up with any ideas? I'm assuming you want a mexican type theme.
If you want it more healthy... salsa instead of a cheesy dip is a lot better for you. Or there are black bean salsas..You can also make salsas that would appeal to the sweet side - fruit salsa with pineapple, etc in it and serve it with baked tortillas.
Quesadillas are an easy thing to make - my kids adore them. You could make your own taco/burrito/fajita bar.. let people make their own and pick their own toppings. My kids love when they can make their own stuff.
Just some ideas