You have a bad age there, but there is hope. Part of the problem is what you call camping.....
If you go to a parking lot with a swimming pool, that will wear out fast. About the only option there is if they have come to appreciate the opposite sex. It they are internet addicted, there is little hope. Unless one is musically inclined, then music will attract others.
But, if you go to a campground that has nature nearby, the get binoculars, a bird book and an animal book and start the competition. When they are into finding more than the other has, hang on. Geocache can work well at this also. Music can work here too.
If things are getting tight, bring a tent to put them out in for the night. That is closer to real camping and you might just start something.
Matt