As someone who's:

1) a die-hard foodie
2) increasingly concerned about the quality and environmental impact of my food choices (shopping the local public market every week, avoiding processed foods, cooking from scratch)
3) a gardening geek

... I find The Vertical Farm Project to be incredibly cool. The idea: Because humans are increasingly urban creatures and because we've basically wrecked our existing agricultural land with ecologically poor farming techniques, the answer is to, well, grow up. To give you a sense of the problem:

New York City has a population of approximately 9 million people in all five boroughs, plus the visitor influx. The average per capita annual use of agricultural produce is approximately 711 pounds (12). The combined per capita consumption of the entire population of New York City is nearly 3 million tons, which translates into 266,000 acres of cropland needed solely for growing produce for New York City. The total ecological footprint of food consumption alone for New York City, as a whole, is over 28.8 million acres. This is 1.2% of the total U.S. land area.

The very smart team behind this as-yet theoretical initiative, led by a professor at Columbia University's school of Environmental Health Science, have thought of everything, from wastewater treatment to harnessing the methane produced by agriculture and using as fuel for the enterprise. You can see some very cool designs of what these skyscraper-farms might look like. Here's hoping.