My family was just talking about this last night - my son made fajitas from flank steak and they were too good! We said we should do a party with margaritas and make it all with Mexican/Spanish food. The flank steaks were simply marinated and he used the George Forman to grill the meat. The veggies were broccoli, peppers and onions sauted in a pan. We thought we could do a taco bar the younger kids - they could make their own tacos with all the fixings put out for them. My son also makes an awsome salsa that we could put out with chips. And of course nachos are always simple to make - just put the chips in the oven long enough to melt the cheese.
Just food for thought~