Take any packagin box (bisquik, cereal, etc) and place it in the sand. You have to pick it up with your teeth, while only on one foot (no hands). Each time a player picks it up, you tear a little more off the top of the box. Last man (or woman, if you're into it) standing wins. Faceplants and carnage is the norm.
Bring a quiver of slingshots - your targets are your dead soldiers (cans). Creative games include 3 steps, turn and fire; skeet shots with throw cans, etc. Dangerous and entertaining. And loud at 1am.
Duckie Boat Races
(need 2+ duckies and a little bit or current. on a bend)
Hook a 50' throw rope to the front of your duckie, and float downstream until taut. Somebody says go, and race the other player in a hand-over-hand race to tag the front of the rope. After tagging, you have to chug a beer as you float backwards - can't start your next pull into you finish it. First player to 3 'laps' wins bragging rights.
If that doesn't get yer blood pumping at camp, I can't help you. The only thing left is a drug called "Charlie Sheen"