Bottle Bank via Martha Stewart: transform a used plastic bottle into a cute piggy bank. Could use same idea to made little containers for kids to store their collections too (use bottle with wider opening and don't make slot)
Cool Crafts for Teens to Make and Sell - Creative DIY Projects to Make and Sell - Craft Project Ideas to Make and Sell - Cool and Cheap Craft Projects and DIY Ideas for Teens and Adults to Make and Sell - Fun, Cool and Creative Ways for Teenagers to Make
Bowls made of confetti! Great recycling art project--save all those leftover paper scraps (put in small bowls at each table). Collect a bunch and have the kids cut them up; Then make bowls made from confetti.