How often do you mow your lawn? 20 times a year? Should think about cutting down to 3 times a year now. Most people use a lawn mower which is bad in emitting fume far worse than a car, polluting the environment with loud noise, and get injury from it. It is worse when some people use pesticide, fertilizer and even water their lawns! There has to be some better productive uses of space other than spending money on a useless nice-looking lawn that is almost like concrete.
Challenge: dig up your lawn.