Worldchanging's Jeremy Faludi calls it "reverse-leapfrogging", but is looking for a better name. It's reviving or importing concepts that used to exist:
Green architects in the last twenty years have learned passive-solar design tricks from pre-industrial buildings, both historic ones in their own countries and contemporary buildings in non-industrial societies. (For instance, cool towers come from vernacular middle-eastern architecture.)
Realizing and embracing innovations that were dropped as déclassé, needlessly efficient, our simply outmoded by newer technology; but were in fact ideal adaptations to certain constrained environments:
A newer example that may be successful (it's too early to call yet), is the Texxi service in Liverpool (see Green Car Congress for a good writeup on it). It is what happens when a Central American "Colectivo" (basically a group taxi, filling a somewhat fuzzy niche between normal taxis and buses) gets wired.
In my travels I've always been amazed at local innovations - Jamaica had "route" taxis which followed a (mostly) constrained route, collected a standard fare, but were more nimble than the bus system, and buildings there, like some colonial-age houses here, were built to be cool even in the hot and humid Jamaican midday. And I've always been impressed by the rural bus systems in Latin America and the Caribbean - no set schedule, but incredibly efficient (they leave when they're full) and with an amazing reach. More flippantly, "bag juice" - flavored sugar water (and sometimes real juice) frozen to a firm slushy consistency in a small sealed bag. Low waste, and a great "personal AC" unit to place on your neck and wrists to cool down (and melt the juice to drink!)
Gardening is another simple thing that's really fallen off (confession: I'm reading Animal, Vegetable, Miracle) - simple, economical, with huge rewards in taste and nutrition, not to mention removing some of your food from the oil-thirsty global transport business.
Local, walkable and livable neighborhood design is something else we threw out with cars and highways, and also worth recovering. If you have to drive to get to everything from the grocer to your work, you also unravel the cohesiveness of your neighborhood where you'd run into neighbors at the corner store, make a lasting friendship with its proprietor, and get a touch of exercise in each day as well.
What else have we lost in the past generation that's worth resurrecting?