We're also traveling with a 13 yo and 10 yo on 8/5/07 on Mariner, both boys. From what I've heard, the kids in both groups have so much fun they're hard to pry away!
I can't answer your quesiton regarding the specific activities, but from what I understand they have a FANTASTIC time. I've also heard to get them there for the FIRST meeting. That's when they make friends for the entire week.