I'm in southeast Nebraska. I recently sold my small business and hve my farm ground rented out. I don't want to get into full scale grain farming, but would like to set aside 5 acres or so to mess around with. I have a bunch of tractors from 1930s two cylinders to a 4430. I also have a disc mower, rake and small square baler. Is there a crop I could plant in the spring, cut, rake and bale, sell the hay and then plow or disc the ground or whatever? Rinse and repeat the next year. 
I have done similar with oats years ago. Sow in the spring and cut about the time it started to make grain.