The Magic Washing Machine
One of the great miracles of industrial technology is the transformation of one of the most difficult of household tasks, washing clothes, into one of the easiest. (I'm doing it right now.) Although he doesn't note it in the talk, hand-washing clothes is so onerous that it is one of the first chores people who don't have washing machines contract out to even poorer people. (Some of the commenters, none of whom scrub their jeans by hand, thus see washing machines as destroying jobs.)
But if you don't want to use electricity, there's a new alternative to the old washboard and bucket called The Laundry POD. (h/t Greg Rehmke via Facebook.)