Most of the time camps keep you plenty busy during the day with activities, and there are enough other things to do when there is free time. Sometimes the dining hall is also the activities center, and they have games and stuff you can use during free times.
Possible ideas:
1) Travel versions of your favorite games, Yahtzee, Mancala, Pigs, Farkel. There are travel versions of many board games too.
2) Sketchbook/notebook & colored pencils, if you're artistically inclined, or want to keep a journal of your time at camp. Also to write down names and contact info of your new friends.
3) A camera. I see by another question you were asking about 35mm cameras. Those disposable cameras work pretty good, if you haven't found a regular camera. Just don't be afraid to get in close, and watch your composition. Get the ones with a flash, so you can do pictures at night too. Get two or three right away. They are small and easy to pack. Great fun & memories.
4) Check the literature about camp - do they have a theme or costume night? some camps do. Round up some things for making a costume. With a small sewing kit, or a bunch of safety pins you can even change the way your regular clothes look, or fix them, should they get torn.
Remember these magic words when it gets dark & scary out:
> ohwah
> tahsill
> laygoo
> siam
They really do keep the scary stuff away. It works much better if you and all your friends say them together. Start out saying them over and over, very slowly. Then speed up a little, repeating them faster and faster each time you say the four words. Before long you will be laughing so hard that nothing bad can happen. (get your parents to try it too)
Have a wonderful time at camp!
