The most effective marketing tactics I know are also the most versatile. You can use them anywhere in any number of cases. Here's an idea your prospects will find downright irresistible and you can do anywhere.
Here's what you do. Fill a locked treasure chest with all kinds of goodies -- camp store items, toys, and other items that don't cost you much but have a high perceived valued to kids and prospects.
Then let the first 500 kids or parents who come to your open house or site tour choose a key to the chest at random and try to open it. Make sure only 1 key opens the lock, and 499 keys don't.
This way you only have one lucky winner who gets to keep everything you've placed in the treasure chest.
We do this on the beach at Aloha all the time. Our campers love it. We also do it at open houses, and the mere fact we have the treasure chest there helps increase attendance.
If you decide to try this "treasure chest promotion," market it like crazy beforehand. Let everyone know they could be a lucky winner at your next camp event. This can really build interest and create excitement among prospects, and best of all it works and it's fun!