How would you go about creating a real Hunger Games competition?

I'm trying to put together a mock Hunger Games with me and my friends. It would be in a semi-wooded regional park with about 15 contestants, from dawn until one person is left. I'd use felt tip markers as knives, water balloons with paint for explosives, nerf guns, foam boomerangs, frisbees, etc. I'm still trying to think of ideas, so if anyone who's read the books or knows the general idea behind them has any suggestions, please help me out! Thanks!