Para cord projects are a hit at camp. Head over to Instructables for a tutorial using para cord and two decorative knots to make a wrapped water bottle.
Check this tutorial over at Instructables written by walkalongaviation. This plane is made with Owens Corning Raft-R-Mate available at those big box home building stores.
Elastic band crafts are a very popular craft with preteens and teens. Check out maya*made and her homemade cork loom to make bracelets with elastic bands.