Suzy Bower shares a cool idea on her blog that would be great for a worship experience at camp if you have a creek, lake or pond:
People write down things they want to let go of. This could be a number of things such as regrets they are holding onto, people or situations they overly worried about, or a goodbye to someone who has died. Once this has been written, make a boat out of the paper. Take it to a river, and voilà - a simple but potentially powerful act to symbolise letting these things go. For a Christian audience, the focus could be on letting them go and trusting God with them. Or the letters could be written to ask for forgiveness from God for things. Perhaps you could read a poem or Bible verses, or say a prayer as the boats float away.
She gives more details on her site as well as directions for turning the written prayers into floatable origami boats. (Note: You may want to make plans for retrieving the boats after the worship or be sure to use biodegradable paper and ink.)