Revolution by toilet hacking? That's a bit of an oversimplification, but for the Greywater Guerrillas it's a start. With a focus on water recycling and creative ways to curb waste, this collective of designers, educators, and environmentalists holds workshops, provides tutorials, and hosts tons of useful content on its website, all of which aims to help renters and home owners alike rig their water systems to waste less. Want to hack your toilet? They'll show you how. Want to use shower water to efficiently irrigate your lawn? Yup, that too.