Try this: If you can get to the soil (rake back leaves or whatever) and
If you can loosen the soil (rake, hoe, tractor, whatever) then throw down some soybeans. Be sure the seeds are covered slightly or at least press them down tightly to the soil. Then If you get a good shower of rain, the soybeans will sprout. This is a short term solution because everyone else is right... not much will grow long-term because of lack of direct sunlight.
But, the beans will probably do well enough to attract some deer before they die out. Deer in my area like nothing better than a 3-inch tall soybean. You may have to repeat this several times to keep something growing all summer. However, bear in mind that the first frost will kill the beans anyway. Little work involved but it might help. I would still recommend opening that canopy up with some sort of thinning/harvest. Ifyou have white oaks be sure they are left alone.