“You can use leftover 2-liter plastic bottles to create DIY sprinklers!” says Jeremy Yamaguchi, CEO of Lawn Love. Simply cut three 1"-long slits in one side of an empty plastic 1-liter bottle.

Now a youth group is hoping some 2-liter plastic bottles filled with water and bleach can brighten Kenya’s slums. The soda bottle-as-lightbulb was first discovered in Brazil by mechanic Alfredo ...