MK-
You might as well leave off the prepositional phrase "to a tailgate party". Healthy foods remain healthy regardless of the venue. I really can't see someone bringing raw vegetables and plain yogurt to a tailgate party, but the fact remains that they are healthy.
You could probably save face by bringing some skinless, baked chicken and whole grain bread. Apples and oranges might be well received.
A number of Yeddans have discussed a healthy diet. You can Google USDA and see what our government thinks. http://www.mypyramid.gov/pyramid/index.html.
As a last resort, you could throw in the towel and bring some hot wings and a 12 pack. This is not an answer to your question, but it would certainly earn you kudos from your partying buddies.
JayR