Here is a marvelous idea for re-claiming areas that have been covered with asphalt. Based on the idea that plants often will take root in the cracks you find in concrete. This happens to the sidewalk in front of my house every week. Left to their own devices they will slowly widen the crack and fill in with soil and more plants. So, why not take advantage of this process and help it along in areas of your choosing.
Whole project cost $500 and didn't take near the labor and time it would have to remove the concrete.
[Image: "crack garden"; Captured from Neatorama: http://www.neatorama.com/2009/06/04/the-crack-garden/]