One original all-camp game that I really liked was a large version of the game Pit.
http://en.wikipedia.org/wiki/Pit_(game)
The person who created our version made gigantic (about 3 ft by 1.5 ft or something like that) cards with images familiar to camp such as rock climbing, camp fires, etc. I don't remember if we teamed up by unit or by group but that would vary depending on the size of your units. It may have been made with multiple "decks" of the cards. So then the specialists were in the middle circle (a big circle made of rope on the ground) and the kids would each take turns going in to the middle and handing their card to a specialist who would go find another kid to just swap the first kid's card with. The idea is to get all the same type of card in your "hand."
I played it a few years ago and only once but the rules involved everyone taking a turn running it to the middle before someone could do it twice and probably other things I just forgot. But it's based off of the game from the wikipedia site. Not sure if it will let me post the link so I'll check to see after I post it and adjust as neeeded!
