Try some clover or oats. Make sure that you get enough sunlight(4-6 hrs)on the ground and that the pH is right before you start. Oats are easy and cheap annual, might need a little more sun(never tried them in the woods). Clover(ladino, durana, patriot all perrenial) are perrenials and works pretty well in pretty shady spots. The red clovers can come back in most spots, but usually from seed of the old plants I believe.