One of our favorites was putting a layer of shaving cream on our counselors sheets and under his blanket. It usually wasn't discovered until he hopped into bed. The most dangerous was to take an aerosol can of some sort { like deoderant } and hold a match up in the spray to form a sort of flame thrower. { DO NOT TRY THIS AT HOME OR CAMP }. We thought it was fun to shoot flames through windows after some one had walked by. Why we didn't blow ourselves up is beyond me.