ThinkGeek :: Solar Powered Water Bottle Cap --- note from kelly - bought this for my husband and 12 year old son for 2012 christmas. They are awesome and I think they will like them for camping. but definitely check the bottles you have.
Did you know that you can camp for FREE throughout the United States? It's called dispersed camping or primitive camping. It's totally legal and totally free. We do it all the time! Here's how it w (Camping Hacks Cabin)