Read an interesting article in Grit called Farming in the City about a guy, Ken Dunn who founded the Resource Center which operates a mini "farm" in an urban Chicago lot. Amazingly, City Farm grows over 80 varieties of produce on 1 acre and employs 4 full time people -- not to mention selling to numerous area restaurants and operating an on-site produce stand!
His vision is to turn more (if not all) of Chicago's vacant lots into farms. This is very very cool to me -- for not only is it employing low-income people who might otherwise not have a job at all, but also helping to provide one of the country's hugest urban areas with some of the freshest food available. That's what I call progress!
City Farm even takes some of the local restaurants kitchen "wastes" for their compost pile.
They provide education on food production to visiting schools, too.