This is turning out to be a fairly good year of the wild woods sponge mushrooms. The boys enjoy finding these, so each day I have been eating large portions of these. They never have made me sick, but I know many people eventually stop eating them because one time they will throw up or have diareah, etc.... I believe it is because they cook them in grease or some other method that makes them harder to digest. The mushrooms are best eaten with no other foods; usually they are fried in butter, even though they can be eaten raw.
I assume they provide a source of rare food, because they can grow over night and not like common garden/farm foods. The largest I have ever found is 16 inches tall. Plenty of 12 inch tall mushrooms can be found, with the common mushroom being 2-4 inches tall.
Most outdoor-types enjoy finding the mushrooms even if they don't eat them. The American Mushroom is considered valuable to some people who will pay big $$$ for them. Some reasturants will pay for each mushroom by the piece or by the pound. Some stores sell the dried mushroom for big $$$ by the ounce.
Most of all they are fun to hunt for and grow best 3 weeks out of the year. This year has been better than the past 4-5 years. Many years ago I could find over 1,000 mushrooms per day, while some years you may barely find 200 for the season.