Enjoy the outdoors! Commune with nature. Investigate trees and flowers. Listen to the quiet. Count the stars! If you have to have games, why go camping! (unless, of course your family made you go!) Then leave the games behind and get to know the world and them on a whole new level. Just an old lady's 3 cents worth! (inflation, you know!)
Depending on the ages of the people playing, there's the traditional Hide and Seek, or you can quote from your favorite movies, bring board games, etc. My family likes to play Catch Phrase around the campfire.